Q: A sample of gold has a mass of 19.3 g and a volume of 1.00 cm$$^3. $$What is the density of gold, and which equation should you use to solve this problem?

Density = $$\frac{\text{mass}}{\text{volume}} = \frac{19.3\ \text{g}}{1.00\ \text{cm}^3} = 19.3\ \text{g/cm}^3$$

Q: Convert 0.0250 kilometers to centimeters using the correct prefix multipliers.

$$0.0250\ \text{km} \times \frac{1000\ \text{m}}{1\ \text{km}} \times \frac{100\ \text{cm}}{1\ \text{m}} = 2500\ \text{cm}$$

Q: A patient’s temperature is measured at 39.0 $$^\circC. $$What is this temperature in Kelvin?

$$T(K) = T(^\circ C) + 273.15 = 39.0 + 273.15 = 312.15\ \text{K}$$

Q: A solution is prepared by dissolving 5.00 g of NaCl in enough water to make 250.0 mL of solution. What is the concentration of NaCl in g/L?

$$\frac{5.00\ \text{g}}{0.250\ \text{L}} = 20.0\ \text{g/L}$$

Question 1

A sample of gold has a mass of 19.3 g and a volume of 1.00 cm$$^3. $$What is the density of gold, and which equation should you use to solve this problem?

Accepted Answer

Density = $$\frac{	ext{mass}}{	ext{volume}} = \frac{19.3\ 	ext{g}}{1.00\ 	ext{cm}^3} = 19.3\ 	ext{g/cm}^3$$

Question 2

Convert 0.0250 kilometers to centimeters using the correct prefix multipliers.

Accepted Answer

$$0.0250\ 	ext{km} 	imes \frac{1000\ 	ext{m}}{1\ 	ext{km}} 	imes \frac{100\ 	ext{cm}}{1\ 	ext{m}} = 2500\ 	ext{cm}$$

Question 3

A patient’s temperature is measured at 39.0 $$^\circC. $$What is this temperature in Kelvin?

Accepted Answer

$$T(K) = T(^\circ C) + 273.15 = 39.0 + 273.15 = 312.15\ 	ext{K}$$

Question 4

Which of the following is a heterogeneous mixture?

Accepted Answer

A salad with lettuce, tomatoes, and cucumbers

Question 5

How many significant figures are in the measurement 0.004560 g?

Accepted Answer

4

Question 6

Which of the following is the correct Lewis dot symbol for magnesium (Mg)?

Accepted Answer

Mg with two dots

Question 7

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

Accepted Answer

$$(NH_4$)_2SO_4$$

Question 8

A compound contains 2.00 mol of hydrogen, 1.00 mol of sulfur, and 4.00 mol of oxygen. What is its empirical formula?

Accepted Answer

$$H_2SO_4$$

Question 9

Which of the following is a correct balanced equation for the combustion of methane ($$CH_4) in $$oxygen?

Accepted Answer

$$CH_4 + 2O_2$$ \rightarrow $$CO_2 + 2H_2O$

Question 10

How many moles are in 3.01 × 10$$^{23}$$ molecules of water ($$H_2O$$)? (Avogadro’s number = $$6.02 	imes 10$$^{23}$$)

Accepted Answer

$$0.500$$ mol

Question 11

Which of the following is a molecular compound?

Accepted Answer

$$CO_2$$

Question 12

What is the molar mass of $$Ca(NO_3$)_2$$? (Atomic masses: Ca = 40.1, N = 14.0, O = 16.0)

Accepted Answer

$$164.1\ 	ext{g/mol}$$

Question 13

Which of the following ions is phosphate?

Accepted Answer

$$PO_4$$^{3-}$$

Question 14

A neutral atom of chlorine has an atomic number of 17 and a mass number of 35. How many neutrons does it have?

Accepted Answer

$$35 - 17 = 18$$ neutrons

Question 15

Which of the following is a single displacement reaction?

Accepted Answer

$$Zn + 2HCl \rightarrow $$ZnCl_2$$ + H_2$

Question 16

How many valence electrons does an atom of sulfur (S, atomic number 16) have?

Accepted Answer

6

Question 17

Which of the following is a correct name for $$Na_2SO_4$$?

Accepted Answer

Sodium sulfate

Question 18

A sample of a compound contains only carbon and hydrogen. Which of the following best describes this substance?

Accepted Answer

A pure substance

Question 19

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

Accepted Answer

$$NO_3$$^{-}$$

Question 20

A solution is prepared by dissolving 5.00 g of NaCl in enough water to make 250.0 mL of solution. What is the concentration of NaCl in g/L?

Accepted Answer

$$\frac{5.00\ 	ext{g}}{0.250\ 	ext{L}} = 20.0\ 	ext{g/L}$$

CHE 100 Exam 1 Study Guide Overview and Key Topics

Guida di studio - Domande di pratica

Study guide - Flashcard