Answer: 25.24moles
Explanation:Please see attachment for explanation
What is the percent composition by mass of nitrogen in the compound N2H4 (gram-formula mass = 32 g/mol)?
The percentage composition of the nitrogen in N₂H₄ is 87.5%
The percentage composition of an element in a compound can be obtained by using the following formula:
Percentage = [tex]\frac{mass of element }{mass of compound }[/tex] × 100
With the above formula, we can obtain the percentage composition by mass of nitrogen in N₂H₄ as illustrated below:
Molar mass of N₂H₄ = 32 g/mol
Mass of N in N₂H₄ = 2N = 2 × 14 = 28 g/mol
Percentage composition of Nitrogen =?Percentage = [tex]\frac{mass of element }{mass of compound }[/tex] × 100
Percentage of nitrogen = [tex]\frac{28}{32}[/tex] × 100
Percentage of nitrogen = 0.875 × 100
Percentage of nitrogen = 87.5%Therefore, the percentage composition of the nitrogen in N₂H₄ is 87.5%
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The percent composition by mass of nitrogen in N2H4 is 87.56%.
Explanation:To find the percent composition by mass of nitrogen in N2H4, we must perform the following calculations:
First, calculate the molar mass of the compound. For N2H4, this is 32 g/mol as given.Next, calculate the total mass of nitrogen in one mole of the compound. Nitrogen has an atomic mass of approximately 14.01 g/mol. Since there are two nitrogen atoms in N2H4, the total mass of nitrogen is 2 * 14.01 g/mol = 28.02 g/mol.To find the percent composition of nitrogen, divide the mass of nitrogen in the compound by the molar mass of the compound and multiply by 100:(28.02 g N / 32 g N2H4) × 100 = 87.56%
Therefore, the percent composition of nitrogen in N2H4 is 87.56%.
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16. Why can grinding a solid into a fine powder increase the rate of reaction?
Answer:
The process of grinding or breaking a substance tends to increase the surface area of the substance. When the surface area increases, there is a better chance for reactants to react and form product. Hence, the more the surface area, the more will be the reaction rate.
The increase in surface area causes the substance to collide with more force with the other reactant and as a result, the reaction rate increases.
Answer:
The powder has a greater surface area than the solid.
Explanation:
Suppose 0.09886 M KOH is titrated into 15.00 mL H2SO4 of unknown concentration until the equivalence point is reached. It takes a total volume of 29.25 mL KOH to neutralize the H2SO4.
What is the concentration of the acid? Express the result to the proper number of significant figures based on the limits of data from the problem.
M acid
Answer:
0.09639M
Explanation:
Step 1:
The balanced equation for the reaction. This is given below:
H2SO4 + 2KOH —> K2SO4 + 2H2
The following were obtained from the balanced equation
Mole of the acid (nA) = 1
Mole of the base (nB) = 2
Step 2:
Data obtained from the question. This includes:
Concentration of acid (Ca) =?
Volume of acid (Va) = 15mL
Concentration of base (Cb) = 0.09886M
Volume of base (Vb) = 29.25mL
Step 3:
Determination of the concentration of the acid.
Applying the equation:
CaVa/CbVb = nA/nB
The concentration of the acid can be obtained as follow:
CaVa/CbVb = nA/nB
Ca x 15 / 0.09886 x 29.25 = 1/2
Cross multiply to express in linear form
Ca x 15 x 2 = 0.09886 x 29.25 x 1
Divide both side by 15 x 2
Ca = (0.09886 x 29.25) / (15 x 2)
Ca = 0.09639M
Therefore, the concentration of the acid is 0.09639M
Answer:
0.09639 M acid
Explanation:
A student has 2.99 g of Potassium Permaganate. How many mL of a .532 M solution can the student make?
How does one solve this?
Answer:
Explanation:
you must be know the formula of potassium permaganate is KMnO₄
now you have already in question 2 things ,
1. the molarity of solution = 0.532 M
2. the mass of KMnO₄ = 2.99 g
the molarity law is M = moles of solute / volume (L)
so use this equation to calculate the volume in liter and convert the result to milliliter.
( if the mass unit is gram (g) = volume must be litter (L) and if the mass unit is milligram = volume must be milliliter (ml) )
** first you must use this equation to calculate how many moles do you have in KMnO₄
number of moles = mass (g) / molecular weight "MW" (g/mole )
now you have 2.99 g ( Mentioned in Question )
and you can calculate MW if you now the Chemical formula
so we have KMnO₄
Mw for KMnO₄ = 39 + 55 + 4x16 = 158 g/mole
**( K=39 , Mn=55 , O= 16 )
so number of moles = 2.99 / 158 = 0.018 = 0.02 moles
and if you go back to the molarity law :
Molarity = moles of solute / volume (L)
so 0.532 = 0.02 / volume (L)
Volume (L) = 0.532 x 0.02 = 0.01064 L
convert to ml = 0.01064 x 1000 = 10.64 ml
Good Luck
Not sure....HELP!!!!!!!
What happens to the volume of a gas if the temperature of that gas increases?
A:It increases.
B:It decreases.
C:It stays the same.
Answer:
A it increases
Explanation:
What is the most common way an earthquake changes Earth's landforms? A
The earthoude wears aney rock B
The earthquake scroes out new valleys
C
The earthquake strihs the position of land
D
The earthoude sprezos laca oves a wide area
Answer:
"The earthquake shakes the position of land" is the most common way an earthquake changes Earth's land forms
Explanation:
Most of the times earthquake has been found to be making drastic reforms over the surface. With respect to the movement of ground other surface effects includes variation in the flow of groundwater, landslides and also in the direction flow change of mudflow. It affects the buildings, bridges, pipelines and railways and other important structures. the ground movement takes place due to the movement of underground rocks which found to be breaking near the faults. This release energy that further leads to movement of the tectonic plates. The generation of seismic wave from the energy.
in a labratory activity the density of a sample of vanadium is determined to be 6.9g/cm^3 at room temperature. what is the percent error for the determined value?
answers:
a : 0.15%
b : 0.87%
c : 13%
d : 15%
PLEASE EXPLAIN! please
Answer:
c : 13%
Explanation:
Data Give:
Experimental density of vanadium = 6.9 g/cm³
percent error = ?
Solution:
Formula used to calculate % error
% error = [experimental value -accepted value/accepted value] x 100
The reported accepted density value for vanadium = 6.11 g/cm³
Put value in the above equation
% error = [ 6.9 - 6.11 / 6.11 ] x 100
% error = [ 0.79 / 6.11 ] x 100
% error = [ 0.129] x 100
% error = 12.9
Round to the 2 significant figure
% error = 13 %
So, option c is correct
From either Electronegativity, symbols of elements, ionization energy and atomic radius what is not a trend that varied systematically in the periodic table?
Answer:
Symbols of elements
Explanation:
Symbols of elements corresponding to their names do not vary systematically in the periodic table. The only systematic variation might be an alphabetical order, either ascending or descending, but we don't see this trend in the periodic table.
The other properties, however, vary systematically:
Electronegativity: the closer an element is to fluorine, the more electronegative it is. The closer it is to francium, the less electronegative it is;Ionization energy: it decreases from right to left along the period and down the group, as atomic size increases and there's a lower attraction force between a nucleus and valence electrons;Atomic radius: it increases from right to left along the period and down the group.A 360. mg sample of aspirin, C9H8O4, (molar mass 180. g), is dissolved in enough water to produce 200. mL of solution. What is the molarity of aspirin in a 50. mL sample of this solution?
Answer:
Molarity = 0.01 M
Explanation:
Molarity is used to measure the concentration of a solution. It will be same for the whole solution or a small amount of solution if the solution is homogeneous.
So, Molarity of 200 mL of solution = Molarity of 50 mL of solution
[tex]\mathbf{Molarity = \frac{number \ of \ moles \ of \ solute}{Volume \ of \ solution \ (in \ liters)}}[/tex]
[tex]\mathbf{Moles = \frac{given \ mass \ of \ compound}{molar \ mass \ of \ compound}}[/tex]
given mass of aspirin = 360 mg = 0.36 g
molar mass of aspirin = 180 g
Volume of solution = 200 mL = 0.2 L
[tex]\mathrm{Mole \ of \ Aspirin = \frac{0.36}{180} = \mathbf{0.002 \ moles}}[/tex]
[tex]\mathrm{Molarity = \frac{0.002}{0.2} = \mathbf{0.01 \ M}}[/tex]
Therefore, Molarity = 0.01 M
50. mL of a sample prepared by dissolving 360. mg of aspirin in 200. mL of solution, has a molarity of 0.0100 M.
First, we will convert 360. mg (0.360 g) to moles of aspirin using its molar mass (180. g/mol).
[tex]0.360 g \times \frac{1mol}{180. g} = 2.00 \times 10^{-3} mol[/tex]
2.00 × 10⁻³ moles of aspirin are dissolved in 200. mL (0.200 L) of solution. The molarity of the solution is:
[tex]M = \frac{2.00 \times 10^{-3} mol}{0.200 L} = 0.0100 M[/tex]
The molarity is an intrinsic property, so a 50. mL sample will have the same molarity as the 200. mL solution.
50. mL of a sample prepared by dissolving 360. mg of aspirin in 200. mL of solution, has a molarity of 0.0100 M.
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When ice is placed in lemonade, how does the energy flow?
Answer:
From the lemonade towards the ice
Explanation:
According to the second law of thermodynamics, heat spontaneously flows from hotter objects to colder objects.
In the context of this problem, we have lemonade at, say, room temperature, as well as ice at either equilibrium temperature at the freezing point of water (0 degrees Celsius) or below. This means that the lemonade here is hotter than the ice.
Based on the second law of thermodynamics, heat would flow from the lemonade (the hotter object) towards the ice (the colder object). This is the reason why ice melts: it gains heat from a hotter object and its temperature increases.
in which one of the given formulae of xenon there are 5 segma bond and 3 bi bond
1_xef2o3
2_xef2o2
3_xef3o2
4_xefo
Answer:
[tex]XeO_{3} F_{2}[/tex]
Explanation:
We can see from the structure that there are 5 sigma bonds(2 between Xe & F and 3 between Xe & O) and 3 pi bonds(between Xe and O).
Scientists have observed huge bubbles of gas ejecting from the sun. Which of these events would most likely occur due to this solar condition? (2 points) Question 2 options: 1) decrease in wind velocity 2) decrease in the gravitational force 3) increase in the average temperature of Earth 4) increase in the amount of helium in the atmosphere
Answer:
3) increase in the average temperature of Earth
Explanation:
Coronal mass ejections or CME is the phenomena described as "Scientists have observed huge bubbles of gas ejecting from the sun". Whilst CMEs can happen alongside solar flares, it is also important to know that they can occur by themselves (independently). Solar flares refers to the abrupt release of energy kept in twisted magnetic fields caused by explosions on the Sun.
When these solar flares hit the earth, the gases (gas molecules) in the upper atmosphere such as nitrogen and water vapor are broken up and freed. This new gases then react with molecules in the ozone layer and reduce its layer. Consequently, the result is that there is increase in the average temperature of Earth.
Hence, option 3 is the event most likely to occur due to this solar condition
Answer:
C. increase in the average temperature of Earth
Explanation:
During a chemical reaction
Answer:
In a chemical reaction, only the atoms present in the reactants can end up in the products. No new atoms are created, and no atoms are destroyed. In a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.
Explanation:
explanation is up there ^^
During a chemical reaction, the reactant molecules' chemical bonds are energetically influenced, resulting in the breaking and subsequent rearrangement to form product molecules with new chemical bonds. The best example of this is the reaction of hydrogen and oxygen to produce water, where the initial molecules' bonds are broken and rearranged to form water molecules.
Explanation:The details of what actually takes place during a chemical reaction are a little complex, but fundamentally, it involves the breaking and forming of chemical bonds. During a chemical reaction, the molecules of the reactants are influenced energetically so their chemical bonds are broken and they subsequently rearrange to form product molecules with new chemical bonds. Let's take a simple example: the reaction between hydrogen and oxygen to yield water:
H₂ + O₂ → H₂O
In this reaction, the chemical bonds within the hydrogen and oxygen molecules are broken and new ones are formed to create a water molecule. This process results in the release of energy.
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What is the name of an ionic compound that
consists of lithium ions (Li+) and iodide ions (I-)?
The ionic compound formed from lithium ions (Li+) and iodide ions (I-) is Lithium Iodide (LiI). This is an example of an ionic compound, which typically forms when a metal reacts with a nonmetal.
The ionic compound that consists of lithium ions (Li+) and iodide ions (I-) is called Lithium Iodide, denoted as LiI. In this compound, lithium is a metal and iodide is a nonmetal, making the compound ionic. The lithium atom donates an electron, forming a Li+ ion, and the iodine atom accepts an electron, forming an I- ion. Subsequently, the Li+ and I- ions attract each other due to their opposite charges, forming an ionic bond and yielding the ionic compound Lithium Iodide.
Lithium Iodide is just one example of an ionic compound. Ionic compounds typically form when a metal reacts with a nonmetal. Other examples can include sodium chloride (NaCl), and calcium chloride (CaCl2), where a transfer of electrons occurs, producing ions.
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Lithium iodide is the name of the ionic compound made up of lithium ions (Li+) and iodide ions (I-). The compound's formula is LiI. The name follows the standard naming convention for ionic compounds.
An ionic compound consisting of lithium ions (Li⁺) and iodide ions (I⁻) is known as lithium iodide. The metal cation name—in this case, lithium—should come first when naming ionic compounds. This is succeeded by the non-metal anion's name, iodine, with a modified '-ide' at the end. Iodine is therefore substituted with iodide.
This naming scheme makes the compound's ionic nature easier to identify. Iodide ions have a 1 charge, signifying that they have gained one electron, whereas lithium ions have a 1+ charge, signifying that they have lost one electron. With the help of their mutual attraction, these opposing charges balance one another out to create a neutral compound with the chemical formula LiI.
As a result, one lithium ion and one iodide ion form the compound lithium iodide, illustrating the basic ideas behind the synthesis and nomenclature of ionic compounds.
Aerobic organisms are more active and efficient users of energy true or false
PLEASE HELP!!
1.)
What would be the effect on the nucleus of an atom if it emitted one alpha particle and one gamma ray?
a decrease of two in atomic number and a decrease of four in mass number
an increase of one in atomic number and a decrease of two in mass number
an increase of one in atomic number and an increase of two in mass number
an increase of two in atomic number and an increase of four in mass number
2.)
When is nuclear decay by beta particle emission more common in atoms?
have an atomic number greater than 83
have a high proton to neutron ratio
have a high neutron to proton ratio
have a low proton to neutron ratio
3.)
If an atom of polonium-218 were to undergo positron emission, which nuclide would result?
bismuth-218
bismuth-217
astatine-218
astatine-217
4.)
A certain chemical reaction experiences a 7.50 × 10-7 kilogram loss in mass. If this mass were to be totally converted to energy, what would be the magnitude of that energy? (1 J = 1 )
1.20 × 1023 J
2.5 × 109 J
4.00 × 101 J
6.75 × 1010 J
Answer: (a)
Decrease of two in atomic number and a decrease of four in mass number
Explanation:
The effect on the nucleus of an atom if it emitted one alpha particle and one gamma ray is:
Alpha (α) particles are like He+2 nucleus which has 2 protons and 2 neutrons. Thus after emitting α particles there will be decrease of atomic number by 2 and mass number will be decreased by 4. And the emission of gamma ray does not produce effect on the number of protons and neutrons.
7. How many protons, neutrons, and electrons are in the following atoms? (a) 40Ar (b) 65Zn (c) 70Ga (d) 80Br (e) 184W (f) 243Am.
Answers:
a) 18 protons, 22 neutrons and 18 electrons
b) 30 protons, 35 neutrons and 30 electrons
c) 31 protons, 39 neutrons and 31 electrons
d) 35 protons, 45 neutrons and 35 electrons
e) 74 protons, 110 neutrons and 74 electrons
f) 95 protons, 148 neutrons and 95 electrons
Explanation:
When we search an element in the Periodic Table, we can find its Atomic number (Z) and its Mass number (A).
Let's talk about them:
Assuming we are deailling with neutral atoms, which have the same number of electrons as number of protons, the atomic number Z indicates us the number of protons and electrons an atom has.
On the other hand, the mass number A gives us information about the number of protons and neutrons in the atom:
A=Z+number of neutrons
Hence:
number of neutrons=A-Z
So, taking this into account let's begin with the answers:
a) Argon (Ar)Z=18
A=39.948 u
number of neutrons=39.948-18=[tex]21.948 \approx 22[/tex]
This means the Argon atom has:18 protons, 22 neutrons and 18 electrons
b) Zinc (Zn)
Z=30
A=65.38 u
number of neutrons=65.38-30=[tex]35.38 \approx 35[/tex]
This means the Zinc atom has: 30 protons, 35 neutrons and 30 electrons
c) Gallium (Ga)
Z=31
A=69.723 u
number of neutrons=69.723-31=[tex]38.72 \approx 39[/tex]
This means the Gallium atom has: 31 protons, 39 neutrons and 31 electrons
d) Bromine (Br)
Z=35
A=79.904 u
number of neutrons=79.904-35=[tex]44.904 \approx 45[/tex]
This means the Bromine atom has: 35 protons, 45 neutrons and 35 electrons
e) Wolframium (Tungsten) (W)
Z=74
A=183.84 u
number of neutrons=183.84-74=[tex]109.84 \approx 110[/tex]
This means the Wolframium atom has: 74 protons, 110 neutrons and 74 electrons
f) Americium (Am)
Z=95
A=243 u
number of neutrons=243-95=148
This means the Americium atom has:95 protons, 148 neutrons and 95 electrons
Identify and explain what can be done to reverse some of the threats posed by a lack of water availability in certain parts of the world.
Answer and Explanation:
Definition of Terms
Lack of water availability is a natural situation that occurs where and when water becomes scarce and not readily available for use.
Possible Threats
Most of the threats caused b water lack of water availability are caused by human activities both necessary and unnecessary while others are caused by nature responding to some of those human activities. These threats include pollution, change of landscape, urban growth, deforestation and climate change.
How to reverse these threats
Implementing adequate hydrologically-based water assessment and management processes:
Landscape changes which are inevitable, are of different types and therefore poses different specific impact on the ecosystems directly or on water availability indirectly. The strength of the impacts will vary with a wide range of possible landscape changes depending the settings conditions. For this reason, it is imperative that for certain parts of the world where the threat of water availability is experienced that adequate hydrologically-based water assessment and management processes be implemented.
Developing optimum, scalable and energy efficient plants for desalination:
For man ears desalination has helped solved lack of water availability in certain parts of the world, but these desalination plants are energy-intensive. However, with newer technologies, these plants would require less energy and when utilized would reverse the threats posed by lack of water availability.
Innovative water catchment and harvesting:
Water catchment systems are imperative for areas with lack of water availability in order to store more waters as gotten from other sources where it is readily available, whilst also recycling the waste waters in those areas too.
Better policies and regulations while educating the masses:
Lack of water availability would affect food security and even cause pollution, therefore the government would need to make better policies and regulations guiding the use of water whilst educating the masses on the need to change their water consumption and lifestyles. And this is easily done when the water available is appropriately priced.
Holistic Ecosystem management:
This type of management means taking into account the ecological, economic and cultural goals that affects the country's natural resources, and this approach has to be holistic, logical and practical. Why holistic approach? Simply because each aspect is related to and influenced by the others.
Improved Distribution Infrastructure:
Poor infrastructure poses threats to health and even the nations economy. The infrastructural system in place for waver distribution must be of good quality and constantly checked and maintained.
The above stated approach would reverse lack of water availability in any nation.
What is a cation and anion?
A cation is a positively charged ion formed by the loss of electrons, whereas an anion is a negatively charged ion formed by the gain of electrons.
A cation is an ion with a positive charge, which occurs when an atom loses one or more electrons. This loss of electrons means that there are more protons than electrons in the cation. On the other hand, an anion is an ion with a negative charge, formed when an atom gains electrons, resulting in more electrons than protons. The sizes of ions change compared to their parent atoms; a cation is always smaller while an anion is larger.
Ions, including cations and anions, are crucial in the formation of ionic compounds. For example, in the compound NaCl, sodium (Na) becomes a cation (Na+) as it loses an electron, and chlorine (Cl) becomes an anion (Cl-) as it gains that electron, forming a neutral compound based on the simplest whole-number ratio of ions.
Which one of the following exhibits dipole-dipole attraction between molecules? Group of answer choices SF6 HCl O2 CF4 C10H22
Answer:
The correct answer is HCl
Explanation:
There is a dipole-dipole force in hydrochloric acid (HCl), this type of attraction occurs in polar covalent molecules. In this case, the positive end of the molecule (H) attracts the negative (Cl).
OPTION B.
HCl, or hydrogen chloride, is the molecule from the given list that exhibits dipole-dipole attraction due to its polar covalent bond and the significant difference in electronegativity between hydrogen and chlorine.
Explanation:The question you've asked is related to dipole-dipole interactions, which occur between molecules that are polar, meaning they have a separation of charges. A polar molecule has a partial positive charge on one side and a partial negative charge on the other. Looking at the list provided, HCl (hydrogen chloride) is the molecule that exhibits dipole-dipole attraction between its molecules, as it consists of a polar covalent bond between hydrogen and chlorine, leading to a significant difference in electronegativity and therefore a permanent dipole.
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What is the number of moles of NaOH in 16.5 mL of 0.750 Molar NaOH?
Answer:
0.0165 (L) * 0.750 (mol/L) = 0.0124 mol NaOH in 16.5 mL
Explanation:
How would you balance the following equation NaOh + H2CO3=Na2CO3+H2O ?
Answer: put 2 in front of NaOH and 2 also in front of H2O
Explanation: 2NaOH + H2CO3 —> Na2CO3 + 2H2O
Consider the half reactions below for a chemical reaction.
Zn--->Zn²⁺(aq)+2e⁻
Cu²⁺(aq)+2e⁻--->Cu(s)
What is the overall equation for this chemical reaction?
Explanation:
Redox couple
It is defined as : having together the oxidized and reduced forms of a substance taking part in oxidation or reduction half reactions .they are actually conjugate acid base pairs
.we can also define it as : an oxidizing and reducing agent which appear on opposite sides of a half equation constitute the redox couple .Like, given below is the cell in which we consider Zn/Cu redox couple .
Electrochemical cell
• Electrochemical cell is the cell in which chemical energy gets converted to electric energy.
• In it indirect redox reactions takes place.
• These reactions are spontaneous that is free energy change for this reaction is negative.
• This cell consists of two half cells.
• In one half cell , there is a aqueous 1molar Zinc sulphate solution with Zinc rod dipped in it.
• In other half cell, there is a 1 molar aqueous solution of Copper sulphate solution with Copper rod dipped in it.
• These electrodes by means of wire are attached to galvanometer.
• A U-shaped tube is taken, which is sealed from both the ends with cotton plug.
• In this, the electrolyte that is inert electrolyte is taken like Potassium nitrate, Ammonium nitrate etc. The electrolyte present is in semi-liquid state.
Observations
With time we see that Zinc rod loses weight, as it has more tendency to loose electrons that is:
These electrons released by zinc, travel to another beaker by means of wire. In doing so, they cause deflection in galvanometer and produce current. This current travel in the direction opposite to the flow of electrons.
These electrons move to another half cell, where copper ions gain these electrons that is reduction occur. As a result, copper metal start depositing on electrode.
The overall reaction that occurs is shown below:
Zn + Cu²⁺ ---> Zn²⁺ + Cu Zn --> getting oxidised and act as anode Cu --> getting reduced and act as cathode
Answer:
A. Zn(s)+Cu2+(aq)--->Zn2+(aq)+Cu(s)
Explanation:
describe in your own words a person of charles law
Answer: the graph of Charles' law is a graph that passes through the origin in which as one variable increases, the other also increases and vice versa.
Explanation:
why do magnesium and oxygen combine?
Answer:
Becuse magnesium is a earth alkaline metal and oxygen is a nonmetal(read explanation)
Explanation:
Magnesium has 2 valence electrons where oxygen has 6 valence electrons. Magnesium has tendency to give electrons to oxygen and oxygen has tendency to gain electrons. They are both trying to complete their last shell to 8 which is called the octet rule. Because they both want to complete each other because of the reasons that I told they combine to be stanle atoms like noble gases.
If the latent heat of fusion for water is 333.4 J/g, how much heat is required to melt 170 grams of ice at 0 °C?
Answer:
The answer in the comments is wrong! It's not even an option on the test. Just letting people know.
Explanation:
Whats 5+5?
.
.
.
.
.
.
.
.
Answer:
The answer is 10
Explanation:
5+5=10
Answer:
10 is your answer um that's it
Water has a boiling point of 100.0°C and a Kb of 0.512°C/m. What is the boiling point of a 8.5 m solution of Mg3(PO4)2 in water?
Answer:
121.76 °C
Explanation:
Data Given:
Boiling point of water = 100.0°C
Kb (boiling point constant = 0.512°C/m
Concentration of the Mg₃(PO₄)₂ = 8.5 m
Solution:
Formula Used to find out boiling point
ΔTb = m.Kb.i . . . . . . (1)
where
ΔTb = boiling point elevation
m = concentration of solution
kb = molal boiling point elevation constant
i = Van't Hoff factor
Van't Hoff factor : It is the number of ions of ionic compound in the solution produced by it when it dissolve in solvent.
Van't Hoff factor for Mg₃(PO₄)₂:
Assuming ideal Van't Hoff factor Look for ionization of Mg₃(PO₄)₂ in solution
Mg₃(PO₄)₂ ------> 3 Mg²⁺ + 2 PO₄³⁻
From above equation it is clear that it give total 5 ions in solution form upon dissolving i.e. 3 Mg²⁺ ions and 2 PO₄³⁻ ions.
So,
Van't Hoff factor = 5
Now
As,
ΔTb = boiling point of solution - boiling point of water
So,
we can write equation 1 as under
Tb (Solution) -Tb (water) = m.Kb.i
As we have to find out boiling point so rearrange the above equation
Tb (Solution) = (m . Kb . i)+ Tb (water) . . . . . . . (2)
Put values in Equation 2
Tb (Solution) = (8.5 m x 0.512°C/m x 5) + 100.0°C
Tb (Solution) = 21.76 °C + 100.0°C
Tb (Solution) = 121.76°C
so the boiling point of 8.5m Mg₃(PO₄)₂ solution = 121.76 °C
How much heat is released by the combustion of 2 mol of methane?
A.-80.3 kJ
B.-802.5 kJ
C.-1,605.1 kJ
D.-6,420.3 kJ
Answer:
C) 1,605.1kJ
Explanation:
Combustion of methane (CH4) is known to be an exothermic reaction. 802.3kJ/mol CH4 (50.1kJ/g) of heat is released during combustion.
If 2 mol of CH4 is combusted
2 × 802.3kJ = 1,604.6kJ of heat is released
1,604.6 ≈ 1605.1kJ