Q: A sample contains 2.0 mol of water ($\mathrm{H_2O}$). How many molecules of water are present in the sample? ($N_A = 6.022 \times 10^{23}\ \mathrm{mol}^{-1}$)

$1.20 \times 10^{24}$ molecules

Q: A sample contains $18.0$ g of glucose ($\mathrm{C_6H_{12}O_6}$, molar mass $180.0\ \mathrm{g/mol}$). How many molecules of glucose are present?

$6.02 \times 10^{22}$ molecules

Question 1

A student is given a mixture of sand and salt. Which separation technique would be most effective to separate the two, and why?

Accepted Answer

Filtration, because sand is insoluble in water while salt is soluble.

Question 2

Which of the following is a chemical property?

Accepted Answer

Reactivity with oxygen

Question 3

A student measures the mass of a sample three times and records the values: 5.12 g, 5.13 g, and 5.11 g. The true mass is 5.50 g. Which statement best describes the data?

Accepted Answer

The measurements are precise but not accurate.

Question 4

Which experiment provided evidence for the existence of the nucleus in the atom?

Accepted Answer

Rutherford's gold foil experiment

Question 5

A sample contains 2.0 mol of water ($\mathrm{H_2O}$). How many molecules of water are present in the sample? ($N_A = 6.022 	imes 10^{23}\ \mathrm{mol}^{-1}$)

Accepted Answer

$1.20 	imes 10^{24}$ molecules

Question 6

Which of the following statements is consistent with Dalton’s atomic theory?

Accepted Answer

All atoms of a given element are identical in mass and properties.

Question 7

A nuclide symbol is written as $^{37}_{17}\mathrm{Cl}$. How many neutrons are present in this isotope?

Accepted Answer

20

Question 8

Which of the following elements is a metalloid?

Accepted Answer

Silicon ($\mathrm{Si}$)

Question 9

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$\mathrm{CH_2O}$

Question 10

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms bonded together; a compound contains two or more different elements bonded together.

Question 11

Which of the following is a homonuclear diatomic element?

Accepted Answer

$\mathrm{O_2}$

Question 12

What is the formula mass of sodium sulfate ($\mathrm{Na_2SO_4}$)? (Atomic masses: $\mathrm{Na} = 23.0$, $\mathrm{S} = 32.1$, $\mathrm{O} = 16.0$)

Accepted Answer

$142.1\ \mathrm{g/mol}$

Question 13

A sample of magnesium contains $1.20 	imes 10^{24}$ atoms. How many moles of magnesium are present? ($N_A = 6.022 	imes 10^{23}\ \mathrm{mol}^{-1}$)

Accepted Answer

$2.00$ mol

Question 14

Which of the following compounds is ionic?

Accepted Answer

$\mathrm{NaCl}$

Question 15

A mass spectrum of an element shows two isotopes with masses 10 amu (abundance 20%) and 11 amu (abundance 80%). What is the average atomic mass?

Accepted Answer

$10.8$ amu

Question 16

Which of the following is the correct name for $\mathrm{Fe_2O_3}$?

Accepted Answer

Iron(III) oxide

Question 17

Which of the following is an organic compound?

Accepted Answer

$\mathrm{CH_3CH_2OH}$

Question 18

A sample contains $18.0$ g of glucose ($\mathrm{C_6H_{12}O_6}$, molar mass $180.0\ \mathrm{g/mol}$). How many molecules of glucose are present?

Accepted Answer

$6.02 	imes 10^{22}$ molecules

Question 19

Which of the following functional groups is present in acetic acid ($\mathrm{CH_3COOH}$)?

Accepted Answer

Carboxylic acid

Question 20

A student analyzes a compound and finds it contains only carbon and hydrogen, with a molar mass of $58\ \mathrm{g/mol}$. Which of the following is the correct molecular formula?

Accepted Answer

$\mathrm{C_4H_{10}}$

CHEM 134 Exam 1 Study Guide: Matter, Atoms, Elements, Molecules & Compounds

Study Guide - Practice Questions

Study Guide - Flashcards