8. Determine the number of significant figures in the following numbers

An asteroid flying through the vacuum of space is an example of inertia where it maintains its motion due to the absence of external forces except gravity. Other examples involving bullets, planes, and softballs are influenced by external forces and hence do not demonstrate inertia in its pure form.

Inertia and Its Examples

Inertia is the resistance of any physical object to a change in its velocity. This includes changes to the object's speed, or direction of motion. An object that isn't influenced by anything other than gravity is considered to be in an inertial frame of reference.

An example of inertia is an asteroid flying through the vacuum of space. This is because the asteroid will maintain its state of motion - traveling at a constant velocity - until acted upon by an outside force, such as another object's gravity. It fits the definition of an inertial frame as it is not being affected by any external forces except gravity, which doesn't change its velocity (considering the incredibly vast distances in space where gravitational influences are relatively minor).

In contrast, a bullet striking a hard surface, a plane taking off from the runway, and catching a softball in a catcher's mitt are all examples where external forces act on the objects, thereby affecting their motions and not illustrating a pure state of inertia.

A bullet striking a hard surface is an example of an object encountering a force that rapidly decelerates it.

A plane taking off is being propelled by the force generated by its engines.

Catching a softball involves an external force applied by the catcher's mitt to stop the ball.

Answer:

False.

Correction: Hydrochloric acid is a strong acid that is monoprotic.

Explanation:

HCl → H⁺ + Cl⁻.

So, the answer is: False.

Hydrochloric acid is a strong acid that is monoprotic.

Answer:

It donates a hydrogen ion

Explanation:

Under the Bronsted-Lowry definition of an acid, acids are protons donors which donate the H+ ion, or the hydrogen ion.

Answer:

The correct option is "it donates a hydrogen ion"

Explanation:

The choice for the last option being the correct answer is because of the Bronsted-Lowry definition of an acid. Bronsted-Lowry acid is a substance that donates a hydrogen ion or a proton.

Consider the reaction below

HCl + NH₃  ⇒ NH₄⁺ + Cl⁻

From the above, we can see that HCl is an example of Bronsted-lowry acid since it donates its hydrogen ion to NH₃ to form NH₄⁺

Answer:

plastic is made from polymers.

Answer:

Explanation:

Assume all the concentrations are expressed in volumetric terms, i.e 10% = 10 liter salt / 100 liter solution, 20% = 20 liter salt / 100 liter soluton, 0% = 0 liters salt.

1) First transformation: 2 liters are from A to B

Solution A:

Solution B:

Resultant mixture in beaker B: 2 liters of solution A plus 2 liters of solution B

2) Second transformation: 1 liter transferred from B to C

                       ↑              ↑

                  (from B)     ( in C)

3) Third transformation: 2 liters are from C to A.

                                       ↑                                    ↑

                                (from C)                             (in A)

Answer:

[tex]\boxed{\text{NH$_{3}$; NH$_{4}$Cl}}[/tex]

Explanation:

The best choice to prepare a buffer of pH 9.0 is a conjugate acid/base pair in which the acid has pKₐ = 9.0 ± 1.

Let's examine each of the choices.

A. NH₃/NH₄Cl

For NH₃, = pK_b = 4.75

For NH₄⁺, pKₐ  14.00 - 4.75 = 9.25

B. HCHO₂/NaCHO₂  

For HCHO₂, pKₐ = 3.74

C. C₅H₅N/ C₅H₅NHCl

For C₅H₅N, = pK_b = 8.76

For C₅H₅N⁺, pKₐ  14.00 – 8.76 = 5.21

D. HNO₂/NaNO₂

For HNO₂, pKₐ = 3.33

The only acid with a pKₐ close to 9.0 is the ammonium ion.

The best buffer to prepare a buffer with pH 9.0 is [tex]\boxed{\text{NH$_{3}$; NH$_{4}$Cl}}[/tex]

From the given options, the best combination to prepare a buffer with a PH of 9.0 is given by;

Option 1; NH₃;NH₄Cl

Now, we want to find the best choice to prepare a buffer of pH 9.0. Thus, let us look at each option;

Option 1; NH₃;NH₄Cl

We are given that pK_b for  NH₃ is 4.75

Thus pKₐ for NH₄ is;

NH₄; pKₐ = 14.00 - 4.75

NH₄; pKₐ = 9.25

Option 2; HCHO₂; NaCHO₂  

We are given that pK_a for HCHO₂ is 3.74

HCHO₂; pKₐ = 3.74

Option 3; C₅H₅N; C₅H₅NHCl

We are given that pK_b for C₅H₅N is 8.76

Thus  

For C₅H₅N, = pK_b = 8.76

Thus, pKₐ for C₅H₅N is;

C₅H₅N; pKₐ = 14.00 – 8.76

C₅H₅N; pKₐ = 5.21

Option 4; HNO₂;NaNO₂

We are given pKₐ for HNO₂ as 3.33

HNO₂; pKₐ = 3.33

Looking at all the pKₐ values, the only acid that has a pKₐ close to 9.0 is NH₄ with a pKₐ of 9.25.

In conclusion, the best combination to prepare a buffer with pH of 9.0 is

NH₃;NH₄Cl

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Answer:

The molarity of products is divided by the molarity of reactants.

Explanation:

Are there choices to pick from?

Answer:

CoCl₃ > Li₂SO₄ > NH₄I.

Explanation:

ΔTf = i.Kf.m,

where, ΔTf is the depression in freezing point.

i is the van 't Hoff factor.

Kf is the molal depression constant of water.

m is the molality of the solution.

(1) Li₂SO₄:

i for Li₂SO₄ = no. of particles produced when the substance is dissolved/no. of original particle = 3/1 = 3.

∴ ΔTb for (Li₂SO₄) = i.Kb.m = (3)(Kf)(m) = 3(Kf)(m).

(2) NH₄I:

i for NH₄I = no. of particles produced when the substance is dissolved/no. of original particle = 2/1 = 2.

∴ ΔTb for (NH₄I) = i.Kb.m = (2)(Kf)(m) = 2(Kf)(m).

(3) CoCl₃:

i for CoCl₃ = no. of particles produced when the substance is dissolved/no. of original particle = 4/1 = 4.

∴ ΔTb for (CoCl₃) = i.Kb.m = (4)(Kf)(m) = 4(Kf)(m).

CoCl₃ > Li₂SO₄ > NH₄I.

Final answer:

The aqueous solutions ranked from highest to lowest freezing point, based on the number of ions they produce upon dissociation, is NH4I (highest freezing point), followed by Li2SO4, and then CoCl3 (lowest freezing point).

Explanation:

To rank aqueous solutions by their freezing points when they have equal concentrations and are completely dissociated, we look at the number of ions each compound dissociates into when dissolved. The more ions produced, the lower the freezing point of the solution due to a greater freezing point depression effect. The given solutions are Li2SO4, NH4I, and CoCl3. Li2SO4 dissociates into 3 ions (2 Li+ + SO42-), NH4I dissociates into 2 ions (NH4+ + I-), and CoCl3 dissociates into 4 ions (Co3+ + 3 Cl-). Therefore, the order from highest to lowest freezing point is: NH4I > Li2SO4 > CoCl3.

Answer:

It is given by the concentration of the products divided by the concentration of the reactants

A container holds a pure sample of a radioactive substance with a half-life of 2 hours. The true statements are a, c and d.

a) After 1 hour, less than 50 % of the original atoms in the container will have decayed.

True. The half-life of the radioactive substance is 2 hours, which means that after 1 hour, only half of the original atoms would have decayed. Therefore, less than 50% of the original atoms will have decayed.

b) After 1 hour, more than 50 % of the original atoms in the container will have decayed.

False. As explained in statement (a), after 1 hour, less than 50% of the original atoms will have decayed, not more than 50%.

c) After 2 hours, 50 % of the original atoms in the container will have decayed.

True. The half-life of the radioactive substance is 2 hours, so after 2 hours, exactly 50% of the original atoms will have decayed.

d) After 4 hours, 25 % of the original atoms will have decayed.

True. Since the half-life is 2 hours, after 4 hours (2 half-lives), 50% of the original atoms will have decayed. Therefore, 25% of the original atoms will remain after 4 hours.

e) After 4 hours, the total number of atoms in the container will be reduced by 75 %.

False. After 4 hours, as explained in statement (d), 25% of the original atoms will remain, not 75%. So, the total number of atoms will be reduced by 100% - 25% = 75%, not 75%.

Correct statements: a), c), and d).

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Answer:

Volume and number of moles.

Explanation:

So, no. of moles and V are constant.

P ∝ T,

∴ P1/T1 = P2/T2.

Answer:

Volume and Number of Moles

Explanation:

I hope this helps !! :)

Answer: 1 C6H12O6===> 2 C2H5OH + 2 CO2

75 In the space in your answer booklet, draw a structural formula for the alcohol formed in this reaction. [1]

Explanation:

The correct structural formula for the alcohol formed in this reaction [tex]CH_3-CH_2-OH[/tex] is also called ethanol.

Alcohol is any of a class of organic compounds characterized by one or more hydroxyl (―OH) groups attached to a carbon atom of an alkyl group (hydrocarbon chain).

Ethanol is simple alcohol produced via the fermentation of sugars (such as glucose, fructose, and sucrose) by yeasts because yeasts do this conversion in the absence of oxygen.

The correct structural formula for the alcohol formed in this reaction [tex]CH_3-CH_2-OH[/tex] is also called ethanol.

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Answer:

D)  8.40 L H₂O(g).

Explanation:

2N₂H₄(l) + O₂(g) → N₂(g) + 2H₂O(g),

It is clear that 2.0 moles of N₂H₄ react with 1.0 mole of O₂ to produce 2.0 moles of N₂ and 2.0 moles of H₂O.

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

using cross multiplication:

1.0 mol of O₂ represents → 22.4 L.

??? mol of O₂ represents → 4.2 L.

∴ 4.2 L of O₂ represents = (1.0 mol)(4.2 L)/(22.4 L) = 0.1875 mol.

Using cross multiplication:

1.0 mol of O₂ produce → 2.0 mol of H₂O, from stichiometry.

0.1875 mol of O₂ produce → ??? mol of H₂O.

∴ The no. of moles of H₂O = (2.0 mol)(0.1875 mol)/(1.0 mol) = 3.75 mol.

1.0 mol of H₂O represents → 22.4 L, at STP.

3.75 mol of H₂O represents → ??? L.

∴ The no. of liters of water vapor will be produced = (3.75 mol)(22.4 L)/(1.0 mol) = 8.4 L.

So, the right choice is: D)  8.40 L H₂O(g).

Final answer:

Using the balanced chemical equation, stoichiometry, and Avogadro's law, we determine that if 4.20 liters of O₂ reacts, it will produce 8.40 liters of H₂O vapor. The correct answer is 8.40L of H₂O vapor.

Explanation:

The question involves a stoichiometric calculation based on the balanced chemical equation for the reaction between hydrazine (N₂H₄) and oxygen (O₂) to produce nitrogen gas (N₂) and water vapor (H₂O). At STP (standard temperature and pressure), one mole of any gas occupies 22.4 liters. According to the balanced chemical equation:

N₂H₄(l) + O₂(g) ⇒N₂(g) + 2H₂O(g)

We can see that 1 mole of O₂ reacts with 1 mole of N₂H₄ to produce 2 moles of H₂O. If 4.20 liters of O₂ are reacted, we can use Avogadro's law to determine the volume of H₂O produced, which will be twice the volume of O₂ reacted because of the 1:2 molar ratio. Therefore, the volume of water vapor produced will be:

4.20 L O₂(g) x (2 moles H₂O / 1 mole O₂) = 8.40 L H₂O(g)

The correct answer is 8.40 L H₂O(g), which corresponds to option D.

Answer:

Atoms

Explanation:

Atoms are widely believed to be the most fundamental particle of matter and their basic building blocks. When atoms combines together, they form compounds. Molecules are another units of matter that are made up of tiny particles of atoms.

Answer:

Explanation:

Iodine is a halogen so it is the group (column number) 17 of the periodic table. It is a representative element.

The number of valence electrons for the representative elements is equal to the second digit of the group number. So, group 17 means that iodince has 7 valence electrons.

Now, more formally, the valence electrons are the electrons in the outermost shell of the atom and you can determine how many of them an atom has by doing the electron configuration.

These are the steps:

An iodine atom has seven valence electrons and generally gains one electron to become a negatively charged iodide ion (I-). Iodine is in the 17th group of the periodic table and prefers to achieve a full octet by accepting an additional electron rather than losing seven electrons.

An iodine atom has seven valence electrons. When looking to achieve a stable electronic configuration, iodine typically gains one electron to complete its octet because it is more energetically favorable than losing seven electrons. When an iodine atom gains an electron, it forms a negatively charged ion known as an iodide ion (I-). The formula of the resulting ion is I-.

The atomic number of iodine (53) reveals that a neutral atom of iodine consists of 53 protons and an equal number of electrons. Iodine is a halogen and is part of the 17th group in the periodic table which is characteristic of elements with seven valence electrons. According to the octet rule, atoms tend to bond in such a way that they each end up with eight valence electrons; gaining one electron is the preferred pathway for iodine.

The concept of a hypervalent structure involves molecules that contain more than eight electrons in their valence shell. However, in the case of the triiodide ion, resonance structures without violating the octet rule offer a more accurate representation of the bonding. As iodine tends to form weak bonds, the I2 molecule can dissociate into atomic iodine at a relatively lower energy compared to lighter halogens.

Answer: Option (a) is the correct answer.

Explanation:

Nuclear fission is defined as a reaction in which a heavy nucleus splits into two or more small nuclei along with emission of energy.

For example, [tex]^{235}_{92}U + ^{1}_{0}n \rightarrow ^{139}_{56}Ba + ^{95}_{36}Kr + 3^{1}_{0}n[/tex]

So, the given diagram shows a large nucleus is splitting into two small nuclei. Therefore, it is a nuclear fission reaction.

Whereas a nuclear reaction in which two small nuclei combine together to result into the formation of a large nucleus is known as a nuclear fusion reaction.

Thus, we can conclude that the reaction depicted in the figure would take place in fission reactor.

Answer:

Explanation:

1) Definition of mole fraction: number of moles of a component / number of moles total number of moles.

2) The number of moles of each component is determined from the respective molar mass. Using the letter n for the number of moles of a component:  

3)      CH₄O

        Molar mass CH₄O = 32.04 g/mol

        n₁ = mass CH₄O / 32.04 g/mol

4)  C₂H₆O

        Molar mass C₂H₆O = 46.07 g/mol

        n₂ = C₂H₆O = mass of C₂H₆O / 46.07 g/mol

5) Both masses are equal; call them m.

6) Mole fraction of CH₄O:

Use the letter X for mole fraction.

Cancel the common factor m:

        X₁ =  [ 1 / 32.04] / [1 / 32.04 + 1 /46.07] = 0.590

7) Mole fraction of C₂H₆O

The mole fractions are rounded to three significant figures.

Answer:

Diamonds are composed almost entirely of the element carbon, often with some other impurities in them, such as nitrogen (i.e., pure diamonds are entirely carbon). The element carbon comes in three different natural forms, or allotropes: diamond, graphite, and amorphous.

Explanation:

Answer:

B

Explanation:

The final position of the curve is higher than the original height of the curve, meaning the products have more energy than the reactants.

Hence energy was added for the reactants to become the products.  This is why the reaction is endothermic, because the products retained some of the supplied energy.

Part of the energy supplied was used to overcome the activation energy (the peak of the curve).  However, this extra energy is recuperated as heat once the product is formed.

Answer:

B-

Heat was added to create the product

Explanation:

Just did the quiz on edg

Answer:

Explanation:

The solution containing fluoride ions and hydrogen fluoride (a weak acid) may be chemically represented by this equilibrium equation:

The HCl, a strong acid, added will ionize in water according to this chemical equation:

Then, following Le Chatelir's principle, the addtion of H⁺ ions coming from the HCl dissociation, will increase the concentration of H⁺ in the solution, driving to the consumption of some F⁻ ions, and the production of more HF acid. This is a shift of the equilbrium toward the HF side.

Adding hydrochloric acid to a solution of fluoride ions and hydrogen fluoride will decrease the pH and increase the concentration of hydrofluoric acid while decreasing the concentration of fluoride ions.

When hydrochloric acid (HCl) is added to a solution containing fluoride ions and hydrogen fluoride, it will cause a decrease in the pH of the solution. This is because HCl is a strong acid and it will dissociate completely in water to release hydronium ions (H3O+), resulting in an increase in the solution's acidity. Furthermore, according to Le Chatelier's principle, the addition of HCl will push the equilibrium of the reaction:

HF(aq) + H2O(l) ⇌ H3O+(aq) + F¯(aq)

to the left, meaning that the concentration of hydrofluoric acid (HF) will increase, while the concentration of fluoride ions (F−) will decrease, due to the additional supply of common ions from HCl.

An electrical phenomenon is caused by flow of free electrons from one atom to another. The characteristics of current electricity are opposite to those of static electricity. Wires are made up of conductors such as copper or aluminum. ... Current flows from positive to negative and electron flows from negative to positive.

Answer:

Explanation:

Reaction rate measures the speed of chemical reaction and how they proceed with time.

The theories that have been propounded about reactions rates shows that increasing temperature is very important in chemical reactions.

From observation, chemical reaction rates are controlled by:

Increasing temperature temperature releases heat energy to drive reactions into completing faster. Collisions between reacting particles becomes more as a result of increase in energy. This energy when greater than the activation  energy of the reaction would further influence the effectiveness of collisions between reacting particles. This would therefore make reactions proceed faster with more increase in temperature.

Answer:

Explanation:

Provided all other conditons remain constant (e.g. volume and temperature), the addition of more reactant means the increase of the concentration of the reactant, and so, at constant temperature, more product must be produced to compensate such addition of more reactant.

An equlibrium reaction may be represented by the general expression:

And the equilibrium constant is given by:

Thus, since at constant temperature Kea is constant, the increase of a reactant concentration (A or B are in the denominator) means that the concentration of the products (C and D in the numerator) must increase.

Since, the molecular point of view what happens is that the increase of the concentration of reactions increase the rate of the direct (forward) reaction yielding to the production of more products.

Final answer:

Adding more reactant to a reaction at equilibrium causes the system to shift right, increasing the rate of the forward reaction and leading to the formation of more products until a new equilibrium is established, with the equilibrium constant (Kc) remaining unchanged.

Explanation:

When a chemical reaction has reached equilibrium, adding more reactant to the system causes the equilibrium to shift. The concepts behind this phenomenon are encapsulated by Le Châtelier's Principle, which states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.

In the case where more reactant is added, the equilibrium will shift to the right, meaning that the reaction system will respond by forming more products to relieve the stress caused by the added reactant. This increase in reactant concentration results in a temporary increase in the rate of the forward reaction compared to the reverse reaction, leading to a consumption of the added reactant and an increase in product concentration until a new equilibrium is established.

After the system readjusts, the reaction quotient (Qc) will once again equal the equilibrium constant (Kc), which remains unchanged as it is only affected by temperature. This adjustment process continues until the rate of the forward reaction and the rate of the reverse reaction are equal again. In essence, by adding more of a reactant, one can temporarily push the reaction to produce more products, a strategy often used in industrial processes to increase yield.

Answer:

The basic theme of organization in the periodic table is that elements are divided into groups and periods based on their properties. Elements that exhibit similar properties are placed in the same group while elements that have the similar number of shell are placed in the same period. This arrangement is based basically on the increasing atomic number of the elements in the periodic table. Atomic number is used for the arrangement of the element because it is a fundamental property of all elements.

Answer:  oxidized

Explanation:

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes

oxidized.

Good luck! and sorry if is not the answer ur looking 4!

Answer:

The glucose molecule is oxidized

Explanation:

When glucose loses a hydrogen atom it is losing 1 proton and 1 electron. As it is losing an electron, the glucose is oxidized.

Answer:

false

Explanation:

It is probably super saturated.

Answer:

The answer is b. much precipitation

Explanation:

A front is a strip in which two air masses of different temperatures are separated. An occluded front occurs when a cold front that generally moves more quickly reaches a hot front and merges. The cold air mass, being heavier, stays below, forcing the warmer to rise. When this happens it cools and condenses, causing heavy precipitation.

The occluded fronts cause weak and continuous rains at first with stratiform-type clouds, and later the rains intensify with the arrival of vertically developing clouds, which cause storms.

Answer:

The answer is B.

Explanation:

Answer:

[tex]\boxed{\text{D. }1.5 \times 10^{-3}\text{ mol}}[/tex]

Explanation:

1 mol of Ca = 40.08 g

[tex]\text{Moles of Ca = 0.06 g Ca} \times \dfrac{\text{1 mol Ca}}{\text{40.08 g Ca}} = 1.5 \times 10^{-3}\text{ mol Ca}\\\\\text{The person consumed }\boxed{1.5 \times 10^{-3}\text{ mol Ca}}[/tex]

Final answer:

By dividing the mass of calcium consumed (0.06 g) by its molar mass (40.08 g/mol), we calculate that the individual consumed 1.5 x 10⁻³ moles of calcium, corresponding to option D.

Explanation:

The health of bones is strongly tied to adequate calcium intake, which is crucial during periods of bone growth and density increase, such as adolescence. To calculate the number of moles of calcium consumed when a person ingests 0.06 g, we need to use the molar mass of calcium. The molar mass of calcium is approximately 40.08 g/mol.

To find the number of moles (n), we use the formula:

n = mass (g) / Molar mass (g/mol)

For calcium:

n = 0.06 g / 40.08 g/mol = 1.5 x 10⁻³ moles

Therefore, the person consumed 1.5 x 10⁻³ moles of calcium, which corresponds to option D.