Q: A sample contains 4.00 moles of water ($$H_2O). $$How many molecules of water are present in the sample? (Avogadro's number $$= 6.022 \times 10$$^{23}$$)

$$2.41 \times 10$$^{24}$$ molecules

Q: Which of the following is a correct metric conversion?

$$1 \text{ km} = 1000 \text{ m}$$

Q: Which of the following statements about the mole is correct?

A mole contains $$6.022 \times 10$$^{23}$$ representative particles of a substance.

Question 1

Which of the following statements best describes the difference between an element and a compound?

Accepted Answer

An element is a substance that cannot be broken down into simpler substances by chemical means, while a compound is composed of two or more elements chemically combined in fixed proportions.

Question 2

A sample contains 4.00 moles of water ($$H_2O). $$How many molecules of water are present in the sample? (Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$2.41 	imes 10$$^{24}$$ molecules

Question 3

Which of the following is the correct scientific notation for the number 0.000345?

Accepted Answer

$$3.45 	imes 10$$^{-4}$$

Question 4

A student measures the mass of a sample as 12.30 g, 12.28 g, and 12.31 g in three trials. The true mass is 12.00 g. Which statement best describes the accuracy and precision of the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 5

Which of the following is the correct formula for magnesium nitrate?

Accepted Answer

$$Mg(NO_3$)_2$$

Question 6

How many significant figures are in the measurement 0.0045600 g?

Accepted Answer

6

Question 7

Which of the following ions is a polyatomic ion?

Accepted Answer

$$SO_4$$^{2-}$$

Question 8

A compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is the empirical formula of the compound?

Accepted Answer

$$CH_2O$$

Question 9

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two nonmetal atoms.

Question 10

Which of the following is a correct metric conversion?

Accepted Answer

$$1 	ext{ km} = 1000 	ext{ m}$$

Question 11

A sample of sodium chloride ($$NaCl) $$has a mass of 58.44 g. How many moles of $$NaCl$$ are present? (Molar mass of $$NaCl = 58.44 	ext{ g/mol})$$

Accepted Answer

1.00 mol

Question 12

Which of the following is NOT a diatomic molecule in its natural state?

Accepted Answer

$$Ne$$

Question 13

What is the charge on the iron ion in $$Fe_2O_3$$?

Accepted Answer

+3

Question 14

Which of the following best describes the term 'isotope'?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 15

A reaction has a theoretical yield of 10.0 g and an actual yield of 8.0 g. What is the percent yield?

Accepted Answer

$$80\%$$

Question 16

Which of the following is the correct name for $$N_2O_5$$?

Accepted Answer

Dinitrogen pentoxide

Question 17

Which of the following statements about the mole is correct?

Accepted Answer

A mole contains $$6.022 	imes 10$$^{23}$$ representative particles of a substance.

Question 18

Which of the following is the correct order of subatomic particles in terms of increasing mass?

Accepted Answer

Electron \u003c Proton \u003c Neutron

Question 19

A student needs to prepare 250.0 mL of a 0.100 M $$NaCl$$ solution. How many grams of $$NaCl$$ are required? (Molar mass of $$NaCl = 58.44 	ext{ g/mol})$$

Accepted Answer

1.46 g

Question 20

Which of the following best describes a limiting reactant in a chemical reaction?

Accepted Answer

The reactant that is completely consumed first, limiting the amount of product formed.

General Chemistry I: Exam 1 Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard