$$\frac{16.00}{18.02} \times 100\% = 88.9\%$$

$$2.00 \times 6.02 \times 10$$^{23}$$ = 1.20 \times 10$$^{24}$$ atoms

$$40.08 + 2 \times (14.01 + 3 \times 16.00) = 164.10\ g/mol$$

Question 1

Which of the following best describes an intensive property, and which is an example of one?

Accepted Answer

A property that does not depend on the amount of substance present; density is an example.

Question 2

A student mixes sand and salt in a beaker. Which type of mixture is formed, and what is a key property of this mixture?

Accepted Answer

Heterogeneous mixture; the components can be visually distinguished.

Question 3

Which of the following is a chemical change?

Accepted Answer

Rusting of iron

Question 4

Convert a temperature of $$25\ ^\circ C to $$Kelvin.

Accepted Answer

$$25 + 273.15 = 298.15\ K$$

Question 5

A sample of a metal has a mass of $$45.0\ g$$ and a volume of $$15.0\ cm^3$. What is its density?

Accepted Answer

$$3.0\ g/cm^3$

Question 6

Which of the following is the correct scientific notation for the number $$0.000456$$?

Accepted Answer

$$4.56 	imes 10$$^{-4}$$

Question 7

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements are currently arranged by increasing atomic number.

Question 8

Which family of elements is characterized by being highly reactive, having one valence electron, and forming $$+1$$ ions?

Accepted Answer

Alkali metals

Question 9

Which of the following is a correct formula and name for a binary ionic compound formed between magnesium and chlorine?

Accepted Answer

$$MgCl_2$$, magnesium chloride

Question 10

What is the correct name for the compound $$Fe_2$$($$SO_4)_3$?

Accepted Answer

Iron(III) sulfate

Question 11

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$(NH_4$)_2SO_4$$

Question 12

Calculate the percent composition by mass of oxygen in $$H_2O.$$

Accepted Answer

$$\frac{16.00}{18.02} 	imes 100\% = 88.9\%$$

Question 13

A hydrate of copper(II) sulfate has a mass of $$3.97\ g$$ before heating and $$2.54\ g$$ after heating. What is the mass of water lost?

Accepted Answer

$$1.43\ g$$

Question 14

How many atoms are present in $$2.00\ mol of $$carbon?

Accepted Answer

$$2.00 	imes 6.02 	imes 10$$^{23}$$ = 1.20 	imes 10$$^{24}$$ atoms

Question 15

What is the molar mass of $$Ca(NO_3$)_2$$?

Accepted Answer

$$40.08 + 2 	imes (14.01 + 3 	imes 16.00) = 164.10\ g/mol$$

Question 16

A sample of $$N_2$$ gas occupies $$44.8\ L at $$STP. How many moles of $$N_2$$ are present?

Accepted Answer

$$44.8 \div 22.4 = 2.00$$ moles

Question 17

Given the empirical formula $$CH_2O$$ and a molar mass of $$180\ g/mol$$, what is the molecular formula?

Accepted Answer

$$C_6H_{12}O_6$

Question 18

Which of the following statements about transition metals is correct?

Accepted Answer

They often form ions with multiple possible charges.

Question 19

A $$10.0\ g$$ sample of $$NaCl$$ contains how many moles of $$NaCl$$? (Molar mass of $$NaCl = 58.44\ g/mol)$$

Accepted Answer

$$10.0 \div 58.44 = 0.171$$ moles

Question 20

Which of the following is a correct example of a physical property?

Accepted Answer

Boiling point

General Chemistry Study Guide: Matter, Elements, Compounds, and Chemical Calculations

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