Answer: The percent yield of the reaction is 18.7 %
Explanation:
Calculating the theoretical yield:To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of hydrazine = 3.95 g
Molar mass of hydrazine = 32 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of hydrazine}=\frac{3.95g}{32g/mol}=0.123mol[/tex]
The given chemical equation follows:
[tex]N_2H_4(aq.)+O_2(g)\rightarrow N_2(g)+2H_2O(l)[/tex]
By Stoichiometry of the reaction:
1 mole of hydrazine produces 1 mole of nitrogen gas
So, 0.123 moles of hydrazine will produce = [tex]\frac{1}{1}\times 0.123=0.123mol[/tex] of nitrogen gas
Calculating the experimental yield:To calculate the moles of nitrogen gas gas, we use the equation given by ideal gas, which follows:
[tex]PV=nRT[/tex]
where,
P = pressure of the nitrogen gas = 1.00 atm
V = Volume of the nitrogen gas = 0.550 L
T = Temperature of the nitrogen gas = 295 K
R = Gas constant = [tex]0.0821\text{ L. atm }mol^{-1}K^{-1}[/tex]
n = number of moles of the nitrogen gas = ?
Putting values in above equation, we get:
[tex]1.00atm\times 0.555L=n_{N_2}\times 0.0821\text{ L atm }mol^{-1}K^{-1}\times 295K\\\\n_{N_2}=\frac{1.00\times 0.555}{0.0821\times 295}=0.023mol[/tex]
Calculating the percentage yield:To calculate the percentage yield of nitrogen gas, we use the equation:
[tex]\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100[/tex]
Experimental yield of nitrogen gas = 0.023 moles
Theoretical yield of nitrogen gas = 0.123 moles
Putting values in above equation, we get:
[tex]\%\text{ yield of nitrogen gas}=\frac{0.023}{0.123}\times 100\\\\\% \text{yield of nitrogen gas}=18.7\%[/tex]
Hence, the percent yield of the reaction is 18.7 %
Answer:
The percent yield of the reaction is 18.45 %
Explanation:
The reaction is:
N₂H₄(aq) + O₂(g) → N₂(g) + 2H₂O(l)
Ratio between hydrazine and N₂ is 1:1, so 1 mol of hydrazine produces 1 mol of N₂
The molar mass of hydrazine is 32 g/m
The moles we used are : mass / molar mass hydrazine
3.95 g / 32 g/m = 0.123 moles
So, in the 100 % yield reaction, we will produce 0.123 of gas.
Let's apply the Ideal Gases law to find out, the moles of gas that have been produced.
0.550L . 1 atm = n . 0.082 . 295K
(0.550L .1atm) / 0.082 . 295K = n
0.0227 mol = n
So, to find out the percent yield of the reaction we finally make a rule of three
0.123 moles ___ 100 %
0.0227 moles ____ 18.45 %
Based on the graph, how would you BEST describe the speed of the racehorse?
A) constantly decreasing speed
B) both increasing and decreasing speed
C) stopped, starting, and then stopped again
D) starting to move and then increasing speed
Answer:
The correct option is:
D) starting to move and then increasing speed
Explanation:
The speed of the racehorse is given by the slope of the given Distance-time graph.
Speed = Distance/time = Slope of the graph
The slope of the graph keeps increasing.
Hence, the speed of the racehore is increasing.
The distance moved is zero at t=0. Hence, the racehorse has started to move from rest.
Answer:
D
Explanation:
I TOOK IT ON USA TEST PREP
A certain amount of H2S was added to a 2.0 L flask and allowed to come to equilibrium. At equilibrium, 0.072 mol of H2 was found. How many moles of H2S were originally added to the flask?
Answer:
0.098 moles H₂S
Explanation:
The reaction that takes place is
2H₂(g) + S₂(g) ⇄ 2H₂S(g) keq = 7.5We can express the equilibrium constant as:
keq = [H₂S]² / [S₂] [H₂]² = 7.5With the volume we can calculate the equilibrium concentration of H₂:
[H₂] = 0.072 mol / 2.0 L = 0.036 MThe stoichiometric ratio tells us that the concentration of S₂ is half of the concentration of H₂:
[S₂] = [H₂] / 2 = 0.036 M / 2 = 0.018 MNow we can calculate [H₂S]:
7.5 = [H₂S]² / (0.018*0.036²)[H₂S] = 0.013 MSo 0.013 M is the concentration of H₂S at equilibrium.
This would amount to (0.013 M * 2.0 L) 0.026 moles of H₂SThe moles of H₂ at equilibrium are equal to the moles of H₂S that reacted.Initial moles of H₂S - Moles of H₂S that reacted into H₂ = Moles of H₂S at equilibrium
Initial moles of H₂S - 0.072 mol = 0.026 mol
Initial moles of H₂S = 0.098 moles H₂S
The number of moles of H2S initially added to the flask is 0.036 mol, calculated based on the number of moles of H2 gas (0.072 mol) obtained at equilibrium by assuming that each mole of H2S gives two moles of H2.
Explanation:This question deals with the concept of chemical equilibrium in the reaction of hydrogen sulfide gas (H2S). It's assumed in the question that H2S gas dissociates into H2 and S2 according to the equation: H2S(g) ⇌ 2H2(g) + S2(g). When 0.072 mol of H2 is obtained at equilibrium, it implies that each mole of H2S gives two moles of H2. Therefore, the number of moles of H2S that were originally added to the flask would be half of the moles of H2 obtained at the equilibrium. Hence, the moles of H2S originally added to the flask are 0.072 / 2 = 0.036 mol.
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A generic gas, X , is placed in a sealed glass jar and decomposes to form gaseous Y and solid Z . 2 X ( g ) − ⇀ ↽ − Y ( g ) + Z ( s ) How are these equilibrium quantities affected by the initial amount of X ( g ) placed in the container? Assume constant temperature.
Final answer:
The initial amount of gas X does not affect the equilibrium composition of gaseous products at a constant temperature, but more of solid Z will be formed until equilibrium is reached again.
Explanation:
The question concerns how the initial amount of a gas, X, affects the equilibrium quantities when it decomposes to form another gas, Y, and a solid, Z, according to the reaction 2X(g) ⇌ Y(g) + Z(s).
In an equilibrium involving a heterogeneous mixture of gases and solids at a constant temperature, the presence of a solid does not affect the equilibrium composition of the gaseous phase. Whether a small or large amount of the solid is present, the equilibrium composition of the gas remains unchanged.
This is because solids and liquids are pure substances with fixed densities and their concentrations are not included in the equilibrium constant expression. Hence, adding more X(g) would not change the equilibrium concentrations of Y(g), but it would lead to more Z(s) being formed until the equilibrium is re-established.
The National Weather Service routinely supplies atmospheric pressure data to help pilots set their altimeters. The units the NWS uses for atmospheric pressure are inches of mercury. A barometric pressure of 30.51 inches of mercury corresponds to __________ kPa.
a. 77.50
b. 775.0
c. 1.020
d. 103.3
e. 16.01
Answer:
d. 103.3
Explanation:
In the given question, the National Weather Service routinely supplies atmospheric pressure data to help pilots set their altimeters. And the units of atmospheric pressure used for reporting the atmospheric pressure data are inches of mercury. For a barometric pressure of 30.51 inches of mercury, we can calculate the pressure in kPa as follow:
In principle, 3.386 kPa is equivalent to the atmospheric pressure of 1 inch of mercury. Thus, 30.51 inches of mercury is equivalent to 30.51 in *(3.386 kPa/1 in) = 103.307 kPa.
Therefore, a barometric pressure of 30.51 inches of mercury corresponds to _____103.3_____ kPa.
The last time the atmospheric carbon dioxide level was as high as it is today was _________ years ago.
Answer:The last time levels of atmospheric carbon dioxide were this high came during the Pliocene Epoch, which extended from about 5.3 million to 2.6 million years ago
The amount of nutrients present in the tropic level is called the living state.
The accurate answer is very complicated as the amount of carbon dioxide is changes gradually every day. Therefore the exact date to the same ratio of carbon dioxide is difficult to tell.
In my opinion, the amount of carbon dioxide is high as it if for today is 20 years ago when ozone later starts depleting.
Hence, the correct answer is 20 years ago.
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A chemist observes that a large molecule reacts as if it were much smaller. The chemist proposes that the molecule is folded in a way that causes it to react differently than expected and develops a series of experiments to test that proposition. How would the chemist's proposition be classified?
Answer:
Hypothesis
Explanation:
The following steps are applicable when we wish to prove a specific fact:
a hypothesis is made; this is a statement that we provide after some observations and we wish to either prove or deny it;multiple experiments are carried out in order to gather significantly substantial amount of data that can be then further analyzed and any tendencies can be noticed;based on the data gathered, conclusions are made: we either prove or deny the hypothesis. If hypothesis is proved, it may become a theory over long time.In the context of this problem, we're at the first step where we make a hypothesis.
Answer:
whats expert verified????
Explanation:
Miles mixed two unlabeled solutions together. This caused a bad reaction, and a noxious gas was emitted. Which describes what Miles should do?
A. He should use a fire blanket to cover his solutions.
B. He should report the accident and leave the area.
C. He should neutralize the reaction by adding water.
D. He should pour the solution down the sink to stop the gas.
Answer:
B. He should report the accident and leave the area.
Explanation:
Noxious gases are harmful and might cause hallucination or even death. Examples of such gases carbon monoxide (CO) and Ammonia gas (NH3).
Let's look at all the options
All the solutions except for B is increasing his time of contact with the gas. This will increase his exposure and might cause death. The fire blanked in option A is used to cover the fire and NOT the gas. It’s simply not made for it. Also, the blanket material might react with the gas to create additional fumes. He should not neutralize it with water as the solution might contain a group 1 metal e.g. Na (sodium). In that case the container will explode and hydrogen gas will release. Pouring the solution down the sink won’t stop the gas as the reaction has occurred already. It will only make the situation worse as after pouring the mixture, the gas will get more space to spread across the room.Therefore, He should report the accident and leave the area.
Answer:
b
Explanation:
You and a friend are being chased by a bear. under these conditions levels of epinephrine are increased due to metabolism of which of the following amino acids
Answer:
For producing epinephrine , tyrosine is required .
Explanation:
Epinephrine is produced in adrenal medulla, where the amino acid tyrosine is transformed to norepinephrine. An enzyme known as phenylethanolamine N-methyltransferase catalyzes the methylation of norepinephrine to epinephrine.
IF an Axonal Membrane transiently becomes very permeable to Na+ ions then the membrane potential of the cell wall will approach:a. (+)132 mVb. (+)50 mVc. (-)60 mVd. (+)70 mVe. (-)94 mV
Answer:
The correct option is D ((+)70 mV)
Explanation:
IF an Axonal Membrane transiently becomes very permeable to Na+ ions then the membrane potential of the cell wall will approach (+)70 mV.
in example 5.11 of the text the molar volume of n2 at STP is given as 22.42 L/mol how is this number calculatd how does the molar volume of h2 at stp compare th te molar volume of n2
Answer:
V = 22.42 L/mol
N₂ and H₂ Same molar Volume at STP
Explanation:
Data Given:
molar volume of N₂ at STP = 22.42 L/mol
Calculation of molar volume of N₂ at STP = ?
Comparison of molar volume of H₂ and N₂ = ?
Solution:
Molar Volume of Gas:
The volume occupied by 1 mole of any gas at standard temperature and pressure and it is always equal to 22.42 L/ mol
Molar volume can be calculated by using ideal gas formula
PV = nRT
Rearrange the equation for Volume
V = nRT / P . . . . . . . . . (1)
where
P = pressure
V = Volume
T= Temperature
n = Number of moles
R = ideal gas constant
Standard values
P = 1 atm
T = 273 K
n = 1 mole
R = 0.08206 L.atm / mol. K
Now put the value in formula (1) to calculate volume for 1 mole of N₂
V = 1 x 273 K x 0.08206 L.atm / mol. K / 1 atm
V = 22.42 L/mol
Now if we look for the above calculation it will be the same for H₂ or any gas. so if we compare the molar volume of 1 mole N₂ and H₂ it will be the same at STP.
With roof framing, a(n) ______ is a structural member which supports the roof of the building.
Answer:
Rafter also called roof joist.
Explanation:
In roof framing, a rafter serves as the structural member that supports the building's roof. It is part of a rigid structure that is essential for the stability of the roof. Historically, other elements like engaged columns and buttresses were also used to support and stabilize the building structure.
Explanation:With roof framing, a rafter is a structural member that supports the roof of a building. A rafter is part of a rigid structure formed of relatively slender pieces, which are typically joined together to support the roof. This is critical in roofing as it helps distribute the weight of the roof and ensures the stability of the building.
The history of roof construction shows that the types of construction varied based on the available natural materials. Load-bearing walls played a vital role in supporting the roofs and had to be constructed strong enough not only to support themselves but also the roof. If the roof span was too large, the walls could be pushed out and collapse.
how many pairs of electrons do two atoms of oxygen need to share to produce one molecule of O2?
Answer:
2 pairs or 4
Explanation:
Oxygen atom belongs to the group 16 of the periodic table also known as the chalcogen group. Oxygen has atomic number of 8. This means it has 8 protons. Hence, for an electrically neutral oxygen atoms, there are 8 electrons.
These electrons are present in the first two shells. There are two electrons in the first shell also known as the K shell. There are 6 electrons in the valence shell of the oxygen atom which is also the L shell. These six valence electrons are the ones responsible for the chemical bonding with other elements.
As said earlier, oxygen atom has six electrons in its valence shell. This means to complete an octet configuration, there are two more electrons needed for it to achieve the needed stability. These two electrons can be obtained ionically or covalently. This depends on the other atom with which it is entering chemical combination with.
In the case of this question, we know it is another oxygen atom. This means each of these atoms will contribute 2 each to make up 2 pairs or 4 electrons which are then controlled by the nuclei of both atoms
Chemical agents that can occur as by-products of industrial pollution and be consumed by humans are __________.
Answer:
Polychlorinated Biphenyls.
Explanation:
Polychlorinated Biphenyls are man-made chemicals. They are solids, and oily liquid in structure with no taste or small, yellow to clear in color. PCBs are present as a mixture, and very stable at an extreme pressure, and temperature. Basically they are used in electrical equipment such as transformers, and capacitors. High level of PCBs can cause broad spectrum of effects in humans, for example:
1) Increase some liver enzyme level, and cause hepatic damage.
2) Respiratory problems.
3) Dermal lesions.
What type of bonding occurs in a sample of pure barium, Ba? In other words, how is one barium atom held to another barium atom?
Answer:metallic bond
Explanation:
The metallic bond consists of a layer of valence electrons electrostatically attracted to positive metal ions. Hence in a metal such as barium, electrons bind the metal ions together in the metallic crystal lattice of the element.
Potassium-40 decays to argon-40 with a half-life of 1.27×109 yr. What is the age of a rock in which the mass ratio of 40Ar to 40K is 4.2?
The age of a rock with a mass ratio of argon-40 to potassium-40 of 4.2, and a half-life of potassium-40 of 1.27×109 years, is calculated to be approximately 1.7 billion years old using the potassium-argon dating method.
Explanation:Calculating Rock Age Using Potassium-Argon Dating
The question asks for the age of a rock, given that the mass ratio of argon-40 (40Ar) to potassium-40 (40K) is 4.2. To find the age of the rock using the potassium-argon dating method, we can apply the concept that 40K decays into 40Ar with a known half-life. This half-life is given as 1.27×109 years.
Using the given mass ratio of 40Ar to 40K, which is 4.2, we can estimate the number of half-lives that have passed. Each half-life passed will result in the remaining 40K being half of what it was before and an increase in 40Ar. We can express the ratio in terms of the decay equation:
NAr / NK = (e−0.693t/T) / (1 − e−0.693t/T)
Where NAr is the amount of 40Ar, NK is the amount of remaining 40K, t is the age of the rock, and T is the half-life of 40K. Solving for t using the given ratio and half-life, we find that the rock is approximately 1.7 billion years old.
Consider a hypothetical experiment in which the left beaker contains 4 mM NaCl, 9 mM glucose and 10 mM albumin. The right beaker contains 10 mM NaCl, 10 mM glucose and 40 mM albumin. The dialysis membrane is permeable to all substances except albumin. In which direction will glucose move?
Answer:
to the left beaker
Explanation:
In the system above, we have two beakers containing different concentrations of glucose. In addition, the two beakers are separated by a permeable membrane which can allow the movement of glucose from one beaker to another. In order to attain equilibrium conditions, there will be a movement of glucose from the beaker with high glucose concentration (right beaker) to the beaker with low glucose concentration (left beaker).
how many grams of CO are needed to react with an excess of fe2o3 to produce 209.7 g fe
Answer:
Amount of CO required is 157.5 g
Explanation:
Molecular mass of Fe = 55.845 g/mol
Amount of Fe = 209.7 g
[tex]Mol\ of\ Fe=\frac{209.7}{55.845} \\=3.75\ mol[/tex]
Balanced reaction of reduction of Fe2O3 is as follows:
[tex]Fe_2O_3(s) + 3CO (g)\rightarrow 2Fe(s)+3CO_2(g)[/tex]
From the balanced reaction, 2 mol of Fe is produced by 3 mol of CO.
Therefore, 3.75 mol of Fe will be produced by,
[tex]\frac{3}{2} \times 3.75 = 5.625\ mol\ CO[/tex]
Relation between mass and mol is as follows:
Mass = Mol × Molecular formula
Molecular mass of CO = 28 g/mol
Grams of CO required = 5.625 mol × 28 g/mol
= 157.5 g
Amount of CO required is 157.5 g.
Answer:
There are 157.8 grams of CO needed.
Explanation:
Step 1: Data given
Mass of Fe produced = 209.7 grams
Molar mass of Fe2O3 = 159.69 g/mol
Molar mass of Fe = 55.845 g/mol
Step 2: The balanced equation
3CO + Fe2O3 → 2Fe + 3CO2
Step 3: Calculate Moles of Fe
Moles Fe = mass Fe / molar mass Fe
Moles Fe = 209.7 grams / 55.845 g/mol
Moles Fe = 3.755 moles
Step 4: Calculate moles of CO
For 3 moles of CO we need 1 mol of Fe2O3 to produce 2 moles Fe and 3 moles of CO2
For 3.755 moles of Fe we need 3.755 *3/2 = 5.6325 moles of CO
Step 5: Calculate mass of CO
Mass CO = moles CO * molar mass CO
Mass CO = 5.6325 * 28.01 g/mol
Mass CO = 157.8 grams
There are 157.8 grams of CO needed.
How could you describe an acid based on Arrhenius's theory? A. produces OH⁻ in solution. B. produces H⁺ in solution. C. a proton acceptor. D. a proton donor. E. none of the above
Answer:
B. produces H⁺ in solution.
Explanation:
Arrhenius theory:-
The Arrhenius theory was introduced introduced by Swedish scientist named Svante Arrhenius in 1887.
According to the theory, acids are the substances which dissociate in the aqueous medium to produce electrically charged atoms ( may be molecule). Out of these species furnished, one must be a proton or the hydrogen ion, [tex]H^+[/tex].
Base are the substances which dissociate in the aqueous medium to produce electrically charged atoms ( may be molecule). Out of these species furnished, one must be a hydroxide ion, [tex]OH^-[/tex].
Hence, the correct option is:- B. produces H⁺ in solution.
According to Arrhenius's theory, an acid is described as B. produces H⁺ in solution.
Arrhenius defined acids as substances that, when dissolved in water, increase the concentration of hydrogen ions (H⁺) in the solution. This definition is based on the idea that acids dissociate in water to release H⁺ ions, which then combine with water molecules to form hydronium ions (H₃O⁺).
For example, when hydrochloric acid (HCl) is dissolved in water, it dissociates into H⁺ and Cl⁻ ions. The H⁺ ions increase the acidity of the solution. This characteristic is central to the Arrhenius definition of acids, distinguishing them from bases, which are defined by their ability to produce OH⁻ ions in solution.
While other definitions of acids, such as Brønsted-Lowry, describe acids as proton donors, Arrhenius specifically focuses on the increase of H⁺ ions in aqueous solutions.
Recognize the visible part of the electromagnetic spectrum and the relationship between wavelength, frequency, and energy.
The region associated with electromagnetic spectrum which contains light at frequencies and wavelengths that stimulates the rod and cones in the human eye is recognized as the visible region of the electromagnetic spectrum. The eye makes the association with some selected portions of that visible region through color.
Energy is inversely proportional to wavelength and it is directly proportional to the frequency.As the frequency and wavelength are related by a constant (c) we can also write the energy in terms of wavelength by the equation [tex]E = \frac{hc}{\lambda}[/tex].
where h is a Planck's constant,
c is the velocity of the light.
Balance the following chemical equation: \text{CH}_ 4 +CH 4 +start text, C, H, end text, start subscript, 4, end subscript, plus \text{O}_ 2 \rightarrow 2 →start text, O, end text, start subscript, 2, end subscript, right arrow \text{CO}_2 +CO 2 +start text, C, O, end text, start subscript, 2, end subscript, plus \text{H}_2\text{O}H 2 O
Balancing the chemical equation CH₄ + O₂ → CO₂ + H₂O involves making sure that the number of atoms for each element is the same on both sides of the equation. The balanced equation is CH₄ + 2O₂ → CO₂ + 2H₂O.
Explanation:To balance the given chemical equation CH₄ + O₂ → CO₂ + H₂O, start by looking at the number of atoms of each type on both sides of the equation. In the case of methane (CH₄), there is one carbon (C) atom and four hydrogen (H) atoms. On the product side, we have one carbon and two hydrogens in water (H2O), and one carbon in carbon dioxide (CO₂). Two waters must be produced to balance the hydrogen on both sides. This alteration however, affects the oxygen balance. Now, there are two oxygen atoms in CO₂ and one in H₂O (total of 4) on the product side. Hence, there should be 2 O₂ molecules on the reactant side. The balanced equation is thus CH₄ + 2O₂ → CO₂ + 2H₂O.
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The balanced equation is CH₄ + 2 O₂ → CO₂ + 2 H₂O.
To balance the chemical equation CH₄ + O₂ → CO₂ + H₂O, follow these steps:
Balance the carbon atoms: There is 1 carbon atom on both reactant and product sides. So carbon is balanced as is.The balanced chemical equation is CH₄ + 2 O₂ → CO₂ + 2 H₂O. Remember, it’s crucial not to alter the chemical formulas, only the coefficients in front of them to balance the equation.
Drag the correct symbol to the equation. Not all symbols will be used. A plutonium atom undergoes nuclear fission. Identify the missing element in the nuclear equation. 239Pu + 1n ---> ____ + 134Xe + 3 1n 94 0 54 0 Options: 101Zr 40 134Xe 54 105Zr 40 103Zr 40 102Xe 54
Answer:
[tex]_{40}^{103}Zr[/tex]
Explanation:
For any nuclear equation, we should utilize the law of mass conservation and the law of charge conservation. The sum of the masses on the left-hand side of the arrow should be equal to the sum of the masses on the right-hand side of the arrow (those are the superscripts for each nucleus). Similarly, the sums of charges should be equal (this is the law of charge conservation).
Let's say that the missing species is X with a mass of 'M' and charge of 'Z':
[tex]_{94}^{239}Pu+_0^1n\rightarrow _Z^MX+_{54}^{134}Xe+3_0^1n[/tex]
Find mass applying the mass balance law:
[tex]239+1=M+134+3\cdot1\\240 = M+137\\M=240 -137\\M=103[/tex]
This means our particle X has a mass of 103. Let's find the atomic number (the charge) same way:
[tex]94+0=Z+54+3\cdot0\\94=Z+54\\Z=94-54=40[/tex]
The atomic number of our nucleus is 40. That said, we have:
[tex]_{40}^{103}X[/tex]
Find the element in the periodic table with Z = 40. This is Zr. Meaning we can now identify it fully:
[tex]_{40}^{103}Zr[/tex]
How many grams of sucrose would you add to water to make a total of 2.1 L of 9 % solution (mass per volume)? Make your answer's precision to one decimal place.
Answer : The mass of sucrose added to water will be, 189.0 grams.
Explanation :
As we are given that 9 % solution (mass per volume) that means 9 grams of sucrose present in 100 mL volume of solution.
Total given volume of solution = 2.1 L = 2100 mL (1 L = 1000 mL)
Now we have to determine the mass of sucrose in solution.
As, 100 mL of solution contains 9 grams of sucrose
So, 2100 mL of solution contains [tex]\frac{2100mL}{100mL}\times 9g=189.0[/tex] grams of sucrose
Therefore, the mass of sucrose added to water will be, 189.0 grams.
2. Beta Particles
a. What is the mass number of the particle emitted from the nucleus during beta minus (β–) decay?
b. What kind of charge does the particle emitted from the nucleus during beta minus (β–) decay have?
c. What is another name for a beta minus (β–) particle?
d. Write the balanced equation for the alpha decay that is below the “Show Equation.” Label the parent, daughter, and beta particle.
3. Nuclear Decay
a. What happens in the nucleus of an atom when an alpha particle is emitted?
b. What happens in the nucleus of an atom when a beta particle is emitted?
Answer:
Explanation:
a. What is the mass number of the particle emitted from the nucleus during beta minus (β–) decay?
zero
The beta radiations are emitted in this reaction. The one electron is ejected and neutron is converted into proton.
⁴₆C → ¹⁴₇N + ⁰₋₁e
b. What kind of charge does the particle emitted from the nucleus during beta minus (β–) decay have?
Negative charge
Electron is emitted during beta decay and it carry negative charge.
c. What is another name for a beta minus (β–) particle?
Electron
During beta minus decay electron is emitted and neutron is converted into proton.
d. Write the balanced equation for the alpha decay that is below the “Show Equation.” Label the parent, daughter, and beta particle.
Equation is missing
a. What happens in the nucleus of an atom when an alpha particle is emitted?
When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number less than 2 as compared to the starting atom.
b. b. What happens in the nucleus of an atom when a beta particle is emitted?
When nucleus emit the beta particle neutron is converted into proton and this proton stay into the nucleus while at the same time electron is emitted. Thus atomic number is increased by one.
⁴₆C → ¹⁴₇N + ⁰₋₁e
Binary compounds of alkali metals and hydrogen react with water to produce H2(g). The H2 from the reaction of a sample of NaH with an excess of water fills a volume of 0.500 L above the water. The temperature of the gas is 35 ∘C and the total pressure is 755 mmHg .
Answer: Mass of H2 liberated = 0.039g;
Mass of NaH that reacted = 0.468g
Note: This is the complete question (Binary compounds of alkali metals and hydrogen react with water to liberate H2(g). The H2 from the reaction of a sample of NaH with an excess of water fills a volume of 0.510 L above the water. The temperature of the gas is 35 ∘C and the total pressure is 755mmHg . Find the mass of H2 liberated and the mass of NaH that reacted.)
Explanation:
The equation of the reaction is NaH + H2O ---> NaOH + H2O
molar mass of NaH = 24g, molar mass of H2 = 2g
First, The volume, V1, of the gas produced at standard conditions (s.t.p.) is determined using the general gas equation; P1V1/T1 = P2V2/T2
Making V1 subject of the formula; V1 = P2V2T1/P1T2
P1 = 760mHg, P2 = 755mmHg, V1 = ?, V2 = 0.5L, T1 = 0∘C = 273K, T2 = 35 ∘C = 308K
V1 = 755*0.5*273/(760*308) = 0.44L
1 mole or 22.4L of H2 has a mass of 2g;
mass of 0.44L of H2 = 2*0.44/22.4 = 0.039g
From the equation of the reaction, 2g of H2 is produced by 24g of NaH at s.t. p.
0.039g of H2 will be produced by 0.039*24/2 = 0.468g of NaH
40 POINTS What are chemical formulas? Give an example of a chemical formula. (4 points)
Answer:
A chemical formula tells us the number of atoms of each element in a compound. It contains the symbols of the atoms of the elements present in the compound as well as how many there are for each element in the form of subscripts.
Explanation:
EXAMPLES:
H2SO4 : Sulfuric Acid. CH4 : Methane.
C12H22O11 : Sucrose. C3H8 : Propane.
NaHCO3 : Baking Soda. F : Fluoride. F2 : Fluoride.
H2O2 : Peroxide.
C8H10N4O2 : Caffeine.
C9H8O4 : Aspirin.
Zn(NO3)2 : Zinc. CO : Carbon Monoxide. NaOH : Sodium Hydroxide. ...
CnH2nOn : Sugar.
What mass of Compound 1 (MW = 800 g/mol) is contained in the solution used to prepare liposomes that elute at 20 mL by size-exclusion chromatography?
Answer:
Mass of compound 1 is 0.7144g
Explanation:
1 mole of liposomes =22.4L
20mL (0.02L) of liposomes = 0.02/22.4 = 0.000893mole
Number of moles = Mass/Molecular Weight (MW)
Mass = Number of moles × MW = 0.000893 × 800 = 0.7144g
discuss the origin of the line citing the bohr theory of the atom specify any energy transitions that are applicable
Answer:
Niels Bohr states that the line spectrum of the hydrogen atom by assuming that the electron revolve in circular paths and that the paths have an allowable radii. ...
Explanation:
discuss the origin of the line citing the bohr theory of the atom specify any energy transitions that are applicable
Niels Bohr states that the line spectrum of the hydrogen atom by assuming that the electron revolve in circular orbits and that orbits have an allowable radii. ... an absorption spectrum is produced, dark lines in the same position as the bright lines in the emission spectrum of an element are produced.
Bohr Atomic Model. Bohr Atomic Model : In 1913 Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus. ... The atom will be stable in the state with the smallest orbit
Bohr explains to us that electron revolve round the nuclues of an atom and possess energy levels. they can change energy levels
Which type of drum is used for the storage of corrosives such as acids, bases, or oxidizers?
Answer:
Polyethylene Drums
Explanation:
Drums are recognisable barrel-like containers. they are used to store a wide variety of substances, including food-grade materials, corrosive flammable liquids and grease
Drums may be constructed of low-carbon steel, polyethylene and cardboard.
Generally the nature of the chemical dictates the construction of the drum
Polyethylene drums are use for storage of corrosive chemicals such as acid bases, or oxidizers and other materials that cannot be stored in steel containers, because of their chemical structure .
How many seconds are required to produce 4.00 g of aluminum metal from the electrolysis of molten alcl3 with an electrical current of 12.0 a?
Answer: 3618 seconds
Explanation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{4g}{27g/mol}=0.15moles[/tex]
According to mole concept:
1 mole of an atom contains [tex]6.022\times 10^{23}[/tex] number of particles.
We know that:
Charge on 1 electron = [tex]1.6\times 10^{-19}C[/tex]
Charge on 1 mole of electrons = [tex]1.6\times 10^{-19}\times 6.022\times 10^{23}=96500C[/tex]
[tex]AlCl_3\rightarrow Al^{3+}+3Cl^-[/tex]
At cathode: [tex] Al^{3+}+3e^-\rightarrow Al[/tex]
1 mole of aluminium is deposited by = [tex]3\times 96500=289500C[/tex]
Thus 0.15 moles of aluminium is deposited by = [tex]\frac{289500C}{1}\times 0.15=43425C[/tex]
To calculate the time required, we use the equation:
[tex]I=\frac{q}{t}[/tex]
where,
I = current passed =12.0 A
q = total charge = [tex]43425C[/tex]
t = time required in seconds = ?
Putting values in above equation, we get:
[tex]12.0A=\frac{43425C}{t}\\\\t=\frac{43425C}{12.0A}=3618s[/tex]
Hence, the amount of time required to produce 4.00 g of aluminum metal from the electrolysis of molten [tex]AlCl_3[/tex] with an electrical current of 12.0 A is 3618 seconds
A cylinder with a movable piston contains a fixed amount of gas at a constant pressure. Initially, the cylinder contains 0.25 liters of air at 0 degrees Celsius. When the temperature is increased to 35 degrees Celsius, the air will occupy what volume?
a. 0.28 L
b. 0.88 L
c. 8.75 L
d. 35.25 L
Answer:
a. 0.28 L
Explanation:
At constant pressure and number of moles, Using Charle's law
[tex]\frac {V_1}{T_1}=\frac {V_2}{T_2}[/tex]
Given ,
V₁ = 0.25 L
V₂ = ?
T₁ = 0 °C
T₂ = 35 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (0 + 273.15) K = 273.15 K
T₂ = (35 + 273.15) K = 308.15 K
Using above equation as:
[tex]\frac{0.25}{273.15}=\frac{V_2}{308.15}[/tex]
[tex]V_2=\frac{0.25\cdot \:308.15}{273.15}[/tex]
New volume = 0.28 L