Q: A cheetah runs at a speed of 120.7 kilometers per hour. What is that speed in meters per minute? ($$1\text{ mile} = 5280\text{ ft}, 1\text{ mile} = 1.609\text{ km}, 1\text{ ft} = 12\text{ in}, 1\text{ in} = 2.54\text{ cm})$$

$$2.0117 \times 10^3$\text{ m/min}$$

Question 1

A student mixes two colorless solutions in a beaker and observes that the temperature of the beaker decreases. Which statement best explains the energy change in this process?

Accepted Answer

The reaction is endothermic because energy is absorbed.

Question 2

Which of the following is the correct electron configuration for the bromide ion ($$\mathrm{Br^-}$$)?

Accepted Answer

$$1s^22s^22$p^63s^23$p^64s^23$d^{10}4p^6$

Question 3

What is the average atomic mass of silicon ($$\mathrm{Si}) $$given the following data?
Isotope 1: 92.2297%, 27.9769 amu
Isotope 2: 4.6832%, 28.9765 amu
Isotope 3: 3.0872%, 29.9738 amu

Accepted Answer

28.0854 amu

Question 4

Which of the following elements would have a neutral atom with an electron configuration of $$[\mathrm{Xe}]6s^2$?

Accepted Answer

Ba

Question 5

How many total electrons should be included in the Lewis structure for the polyatomic ion sulfate ($$\mathrm{SO_4$^{2-}}$$)?

Accepted Answer

32

Question 6

A cheetah runs at a speed of 120.7 kilometers per hour. What is that speed in meters per minute? ($$1	ext{ mile} = 5280	ext{ ft}, 1	ext{ mile} = 1.609	ext{ km}, 1	ext{ ft} = 12	ext{ in}, 1	ext{ in} = 2.54	ext{ cm})$$

Accepted Answer

$$2.0117 	imes 10^3$	ext{ m/min}$$

Question 7

Which of the following statements about the Lewis structure for ozone ($$\mathrm{O_3$}) is $$correct?

Accepted Answer

This is a valid Lewis structure because the octet rule is satisfied on all oxygen atoms.

Question 8

Which of the following pairs of elements would be paramagnetic neutral atoms within the 2nd period of the periodic table?

Accepted Answer

B, C, O, N

Question 9

How many total atoms are in one molecule of sucrose if its chemical formula can be written as $$\mathrm{C$$_{12}$$H_{22}O$$_{11}}$?

Accepted Answer

54

Question 10

Which of the following statements is true regarding the isotopes $$^1\mathrm{H}$$ and $$^2\mathrm{H}$$?

Accepted Answer

$$^2\mathrm{H}$$ and $$^1\mathrm{H}$$ have the same number of protons.

Question 11

What is the correct name for $$\mathrm{Mg_3$(PO_4$)_2}$$?

Accepted Answer

Magnesium phosphate

Question 12

Which of the following best explains why the Lewis structure below is the best choice for $$\mathrm{CH_2N}$$?

Structure 1: H–C=N–H
Structure 2: H–C≡N–H

Accepted Answer

Structure 2 is better because it has the correct number of valence electrons while Structure 1 does not.

Question 13

Which of the following bonds would have the highest bond energy?

Accepted Answer

A nitrogen-nitrogen triple bond

Question 14

What is the total sum of coefficients once the following reaction has been properly balanced?
$$\mathrm{Ca(s) + H_2O(l) \rightarrow Ca(OH)_2(aq) + H_2$(g)}$$

Accepted Answer

4

Question 15

How many molecules of $$\mathrm{NH_3$}$$ can be produced if you react $$1.87 	imes 10^5$ hydrogen (H) atoms with an excess of $$\mathrm{$$N_2$$}$$?

Accepted Answer

$$6.23 	imes 10^4$

Question 16

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

Accepted Answer

$$\mathrm{Al_2$(SO_4$)_3}$$

Question 17

Which of the following statements about the Lewis structure for $$\mathrm{F_2CO} ($$carbon is the central atom) is correct?

Accepted Answer

All of the above are correct.

Question 18

What is the coefficient for iron oxide ($$\mathrm{Fe_2O_3}) $$for the following reaction once it has been properly balanced?
$$\mathrm{Al(s) + Fe_2O_3(s) \rightarrow Al_2O_3(s) + Fe(s)}$$

Accepted Answer

3

Question 19

Which of the following is incorrectly named?

Accepted Answer

N_2O_5, nitrogen pentoxide

Question 20

Which of the following statements best describes the reaction if the reactants are higher in energy than the products?

Accepted Answer

The reaction is exothermic because energy is released.

General Chemistry: Key Concepts, Calculations, and Applications

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