$$\frac{16.00}{18.02} \times 100\% = 88.8\%$$

$$2.00\ mol \times 6.02 \times 10$$^{23}$$\ molecules/mol \times 3\ atoms/molecule = 3.61 \times 10$$^{24}$$\ atoms$$

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

Question 1

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the individual components are not evenly distributed, such as sand in water.

Question 2

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

Accepted Answer

Burning of gasoline in a car engine.

Question 3

Which of the following is an intensive property?

Accepted Answer

Density

Question 4

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

Accepted Answer

$$25\ ^\circ C = 273.15 + 25 = 298.15\ K$$

Question 5

A sample of gold has a mass of $$96.5\ g$$ and a volume of $$5.00\ cm^3$. What is its density?

Accepted Answer

$$19.3\ g/cm^3$

Question 6

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

Accepted Answer

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

Question 7

Which of the following elements is a halogen?

Accepted Answer

Chlorine

Question 8

Which of the following correctly describes the difference between metals and non-metals?

Accepted Answer

Metals are good conductors of heat and electricity, while non-metals are generally poor conductors.

Question 9

What is the correct name for the compound $$FeCl_3$$?

Accepted Answer

Iron(III) chloride

Question 10

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

Accepted Answer

$$\frac{16.00}{18.02} 	imes 100\% = 88.8\%$$

Question 11

A hydrate of magnesium sulfate has a mass of $$13.52\ g$$ before heating and $$6.60\ g$$ after heating. What is the mass of water lost?

Accepted Answer

$$13.52\ g - 6.60\ g = 6.92\ g$$

Question 12

How many atoms are present in $$2.00\ mol of$$ $$CO_2$$?

Accepted Answer

$$2.00\ mol 	imes 6.02 	imes 10$$^{23}$$\ molecules/mol 	imes 3\ atoms/molecule = 3.61 	imes 10$$^{24}$$\ atoms$$

Question 13

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 14

How many moles are in $$44.8\ L of$$ $$O_2$$ gas at STP?

Accepted Answer

$$\frac{44.8\ L}{22.4\ L/mol} = 2.00\ mol$$

Question 15

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

Accepted Answer

$$CH_2O$$

Question 16

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

Accepted Answer

$$(NH_4$)_2SO_4$$

Question 17

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

Accepted Answer

Elements are currently arranged in order of increasing atomic number.

Question 18

How many significant figures are in the measurement $$0.004560$$?

Accepted Answer

4

Question 19

Which of the following is a physical property?

Accepted Answer

Boiling point

Question 20

A student needs to convert $$250\ mg to $$grams using the factor-label method. What is the correct answer?

Accepted Answer

$$250\ mg 	imes \frac{1\ g}{1000\ mg} = 0.250\ g$$

General Chemistry Study Guide: Matter, Measurement, and Chemical Formulas

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