Q: Which of the following statements about Avogadro’s number is correct?

Avogadro’s number is $$6.02 \times 10$$^{23}$$ and represents the number of particles in one mole of a substance.

Question 1

Which of the following best describes the Law of Conservation of Mass as established by Lavoisier?

Accepted Answer

The total mass of substances present after a chemical reaction is equal to the mass before the reaction.

Question 2

The term 'atom' comes from the Greek word 'atomos.' What does 'atomos' mean?

Accepted Answer

cannot be cut

Question 3

A log burns completely in a campfire, and the mass of the ash is much less than the mass of the original log. According to the law of conservation of mass, what happened to the matter that composed the log?

Accepted Answer

The matter that composed the log reacts to form gases that are released into the air.

Question 4

After a 10 g sample of lithium metal reacts in a closed container with 44.32 g of chlorine gas, 1.32 g of lithium remains and all the chlorine is consumed. What mass of lithium chloride is formed?

Accepted Answer

$$54.32\ \mathrm{g}$$

Question 5

Which of the following is NOT a postulate of Dalton’s Atomic Theory?

Accepted Answer

Atoms are created and destroyed in chemical reactions.

Question 6

Which statement best captures one of the differences between the law of definite proportions and the law of multiple proportions?

Accepted Answer

The law of definite proportions applies to two or more samples of the same compound, while the law of multiple proportions applies to two different compounds containing the same two elements.

Question 7

Two samples of carbon monoxide are decomposed into their constituent elements. One sample produces 17.2 g of oxygen and 12.9 g of carbon, and the other sample produces 10.5 g of oxygen and 7.88 g of carbon. Are these results consistent with the law of definite proportions?

Accepted Answer

Yes, because the ratio of oxygen to carbon is the same in both samples.

Question 8

Nitrogen dioxide contains $$2.28\ \mathrm{g}$$ oxygen to every $$1.00\ \mathrm{g}$$ nitrogen, while dinitrogen monoxide contains $$0.570\ \mathrm{g}$$ oxygen to every $$1.00\ \mathrm{g}$$ nitrogen. What is the ratio of oxygen in nitrogen dioxide to dinitrogen monoxide, and what law does this illustrate?

Accepted Answer

The ratio is $$4:1$$, illustrating the law of multiple proportions.

Question 9

Which chemical law is illustrated by the following data: Compound A contains $$1.333\ \mathrm{g} of $$oxygen per gram of carbon, whereas compound B contains $$2.666\ \mathrm{g} of $$oxygen per gram of carbon?

Accepted Answer

The law of multiple proportions

Question 10

If compound A has an equal number of oxygen and carbon atoms, and compound B contains twice as much oxygen per gram of carbon, what can we conclude about the number of oxygen atoms per carbon atom in compound B?

Accepted Answer

The second compound must have twice as many oxygen atoms per carbon atom as the first compound.

Question 11

In his early periodic table, Mendeleev arranged the known elements into groups primarily according to what criterion?

Accepted Answer

Similar chemical properties

Question 12

Which of the following statements about Avogadro’s number is correct?

Accepted Answer

Avogadro’s number is $$6.02 	imes 10$$^{23}$$ and represents the number of particles in one mole of a substance.

Question 13

How many moles of $$\mathrm{CO}_2$$ are in $$2.50 	imes 10$$^{24}$$ molecules of $$\mathrm{CO}_2$$?

Accepted Answer

$$4.15$$ moles

Question 14

What is the mass, in grams, of $$3.25$$ moles of ammonia, $$\mathrm{NH}_3$$? (Molar mass of $$\mathrm{NH}_3 = 17.03\ \mathrm{g/mol})$$

Accepted Answer

$$55.3\ \mathrm{g}$$

Question 15

Which has more atoms: $$10.0\ \mathrm{g} of Mg or$$ $$10.0\ \mathrm{g} of Ca$$?

Accepted Answer

Magnesium

Question 16

Which of the following has the largest mass?

Accepted Answer

$$10.0$$ mol Rb

Question 17

Isotopes have:

Accepted Answer

The same number of protons, but different numbers of neutrons.

Question 18

Which of the following is correct?

Accepted Answer

All of the above

Question 19

Which reaction is consistent with Dalton’s Atomic Theory?

Accepted Answer

$$\mathrm{C} + \mathrm{H}_2 \rightarrow \mathrm{CH}_4$$

Atoms, Atomic Theory, and the Periodic Table: Foundations of Chemistry

Study Guide - Practice Questions

Study Guide - Flashcards