Question 1

Which of the following best describes the difference between precision and accuracy in a laboratory measurement?

Accepted Answer

Precision is how close repeated measurements are to each other; accuracy is how close a measurement is to the true value.

Question 2

How many significant figures are in the number $$0.00053$$?

Accepted Answer

2

Question 3

A granite block has a mass of $$52\ \mathrm{g}$$ and a density of $$2.6\ \mathrm{g/cm^3$}. $$What is its volume in $$\mathrm{cm^3$}$$?

Accepted Answer

$$20\ \mathrm{cm^3$}$$

Question 4

Room temperature is $$23\ ^\circ\mathrm{C}. $$What is this temperature in Kelvin?

Accepted Answer

$$296.15\ \mathrm{K}$$

Question 5

Which of the following is an example of a chemical change?

Accepted Answer

Burning of a match

Question 6

Which statement best distinguishes a pure substance from a mixture?

Accepted Answer

A pure substance contains only one type of atom or molecule with fixed proportions, while a mixture contains variable proportions of different substances.

Question 7

Which law is illustrated by the fact that every sample of methane contains $$12\ \mathrm{g} of $$carbon for every $$4\ \mathrm{g} of $$hydrogen?

Accepted Answer

Law of definite proportions

Question 8

A sample of chlorine contains two isotopes: $$^{35}\mathrm{Cl} ($$mass $$= 34.96885\ \mathrm{amu}) $$and $$^{37}\mathrm{Cl} ($$mass $$= 36.96590\ \mathrm{amu}). If $$the average atomic mass is $$35.453\ \mathrm{amu}$$, what is the percent abundance of $$^{35}\mathrm{Cl}$$?

Accepted Answer

$$75.76\%$$

Question 9

Which scientist is correctly matched with their major contribution to chemistry?

Accepted Answer

Rutherford – discovered the atomic nucleus

Question 10

What is the most likely ionic charge for a potassium (K) ion?

Accepted Answer

$$+1$$

Question 11

Which of the following compounds is named correctly?

Accepted Answer

V$$_2O$_3$$ – Vanadium(III) oxide

Question 12

What is the empirical formula of a hydrocarbon that produces $$2.81\ \mathrm{g} of$$ $$\mathrm{CO}_2$$ and $$0.576\ \mathrm{g} of$$ $$\mathrm{H}_2\mathrm{O}$$ upon complete combustion?

Accepted Answer

$$\mathrm{CH}$$

Question 13

Which of the following best describes the difference between a theory and a law in science?

Accepted Answer

A law states what happens in nature, while a theory explains why it happens.

Question 14

Which of the following ions is named correctly?

Accepted Answer

$$\mathrm{AsO}_3$$^{3-}$$ – arsenite

Question 15

What is the molecular weight of acetic acid ($$\mathrm{C}_2\mathrm{H}_4\mathrm{O}_2$$)?

Accepted Answer

$$60.0522\ \mathrm{amu}$$

Question 16

Which of the following best explains why methane ($$\mathrm{CH}_4) $$shows a small peak at $$17\ \mathrm{m/z} in a $$mass spectrometry analysis?

Accepted Answer

Methane contains a small amount of a heavier isotope, resulting in a higher $$\mathrm{m/z}$$ peak.

Question 17

Which of the following compounds is most likely to be ionic?

Accepted Answer

$$\mathrm{NaCl}$$

Question 18

What is the correct name for the acid formed when $$\mathrm{HI}$$ dissolves in water?

Accepted Answer

Hydroiodic acid

Question 19

A railroad spike weighs $$1.1\ \mathrm{kg}. $$How many moles of iron atoms does it contain? (Molar mass of Fe $$= 55.85\ \mathrm{g/mol})$$

Accepted Answer

$$19.70\ \mathrm{mol}$$

Question 20

Which of the following is the correct formula and name for the compound formed from strontium and sulfur?

Accepted Answer

$$\mathrm{SrS}$$, strontium sulfide

CHEM1111 Exam 01 Review – Step-by-Step Study Guidance

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