Question 1

A car travels at 850 miles per hour. What is this speed in meters per second? (1 mi = 1.609 km)

Accepted Answer

$$1390 \, \mathrm{m/s}$$

Question 2

What is the percent by mass of gold (Au) in $$\mathrm{Au}_2\mathrm{S}_3$$?

Accepted Answer

$$65.90\%$$

Question 3

Which of the following oxyanions is incorrectly named?

Accepted Answer

$$\mathrm{NO}_2^-$$: nitrite

Question 4

Which of the following is an incorrect representation for a neutral atom?

Accepted Answer

$$^{23}_{12}\mathrm{Ca}$$

Question 5

Which of the following acids is incorrectly named?

Accepted Answer

Sulfuric acid, H$$_2SO$_3$$

Question 6

How many total electrons are there in the chlorite anion?

Accepted Answer

$$20$$

Question 7

Which of the following must be present in an ion?

Accepted Answer

An electron

Question 8

What is the molar mass of potassium nitrite ($$\mathrm{KNO}_2$$)?

Accepted Answer

$$77.0 \, \mathrm{g/mol}$$

Question 9

For the reaction: $$\_\mathrm{CH}_4(g) + \_\mathrm{Br}_2(l) \rightarrow \_\mathrm{CBr}_4(s) + \_\mathrm{HBr}(g)$$, what is the coefficient for bromine ($$\mathrm{Br}_2) $$when the reaction is balanced?

Accepted Answer

$$4$$

Question 10

What is the percentage of nitrogen, by mass, in calcium nitrate ($$\mathrm{Ca(NO}_3)_2$$)?

Accepted Answer

$$17.1\%$$

Question 11

Cyclohexane, a commonly used organic solvent, is $$85.6\% C $$and $$14.4\% H by $$mass. What is its empirical formula?

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}$$

Question 12

In the combustion of the hydrocarbon $$\mathrm{C}_4\mathrm{H}_{10}$$, what is the coefficient for $$\mathrm{O}_2$$ when the reaction is balanced?

Accepted Answer

$$13/2$$

Question 13

Propane, $$\mathrm{C}_3\mathrm{H}_8$$, is a common fuel used for cooking and home heating. What mass of $$\mathrm{O}_2 is $$consumed in the combustion of $$1.00\,\mathrm{g} of $$propane?

Accepted Answer

$$3.63\,\mathrm{g}$$

Question 14

Molten gallium reacts with arsenic to form the semiconductor gallium arsenide, $$\mathrm{GaAs}$$, used in light emitting diodes and solar cells: $$\mathrm{Ga}(l) + \mathrm{As}(s) \rightarrow \mathrm{GaAs}(s). If$$ $$4.00\,\mathrm{g} of $$gallium is reacted with $$5.50\,\mathrm{g} of $$arsenic, how many grams of the excess reactant are left at the end of the reaction?

Accepted Answer

$$1.20\,\mathrm{g}$$ \ As

Question 15

Both titanium and lead have been used as whitening sources for paint. The density of titanium is $$4.50\,\mathrm{g/cm}^3$$; the density of lead is $$11.34\,\mathrm{g/cm}^3. $$How many times heavier would one expect $$2$$ gallons of lead powder to be compared to $$2$$ gallons of titanium powder?

Accepted Answer

$$2.869$$ times heavier

Question 16

An electron has a charge of $$1.602 	imes 10$$^{-19}$$ coulombs (C), a wire with a current of 4.0$ amperes ($$\mathrm{C/s}$$) moving through it has a frequency of how many Hz ($$\mathrm{s}^{-1}$$)?

Accepted Answer

$$2.5 	imes 10$$^{19}$$ Hz

Question 17

In an alternate universe there are only two naturally occurring isotopes of iron: $$^{56}\mathrm{Fe}$$ ($$64.5\%$$ abundance) and $$^{58}\mathrm{Fe}$$ ($$35.5\%$$ abundance). Given this information, what is the atomic weight of iron in this alternate universe?

Accepted Answer

$$56.7$$ amu

Question 18

$$^{24}\mathrm{Mg} is $$the most abundant isotope of magnesium with $$78.99\%$$ abundance. There are two additional naturally occurring magnesium isotopes $$^{25}\mathrm{Mg}$$ and $$^{26}\mathrm{Mg}. $$What is the percent abundance of $$^{25}\mathrm{Mg}$$? Assume the atomic masses are the mass numbers of each isotope.

Accepted Answer

$$10.5\%$$

Question 19

If $$6.0$$ grams of beryllium fluoride is reacted with excess aluminum phosphate to give beryllium phosphate and $$\mathrm{AlF}_3$$, how many grams of beryllium phosphate are produced?

Accepted Answer

$$9.2$$ grams

Question 20

How many moles are in $$12.0 g of$$ $$\mathrm{LiCl}$$?

Accepted Answer

$$0.283$$ moles

General Chemistry 1201: Key Concepts and Practice Questions

Guida di studio - Domande di pratica

Study guide - Flashcard