Question 1

A 21.8 g sample of osmium has a density of $$22.6\ \mathrm{g/cm^3$}. $$What is the volume of the sample in $$\mathrm{cm^3$}$$, reported to the correct number of significant figures?

Accepted Answer

$$0.965\ \mathrm{cm^3$}$$

Question 2

Which of the following best describes the arrangement of elements in the modern Periodic Table?

Accepted Answer

By increasing atomic number

Question 3

A 185-pound man has 1.4% of his mass as calcium. How many kilograms of calcium does he have? ($$1\ \mathrm{kg} = 2.20\ \mathrm{lb})$$

Accepted Answer

$$1.2\ \mathrm{kg}$$

Question 4

A wooden object has a mass of $$10.782\ \mathrm{g}$$ and a volume of $$13.72\ \mathrm{mL}. $$What is its density, reported to the correct number of significant figures?

Accepted Answer

$$0.7859\ \mathrm{g/mL}$$

Question 5

Convert $$229\ \mathrm{K} to $$degrees Celsius.

Accepted Answer

$$-44\ ^\circ\mathrm{C}$$

Question 6

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

Accepted Answer

Grinding coffee beans

Question 7

How many calories are required to raise the temperature of a $$150.\ \mathrm{g}$$ sample of gold from $$25\ ^\circ\mathrm{C} to$$ $$175\ ^\circ\mathrm{C}$$? (Specific heat of gold $$= 0.0308\ \mathrm{cal/g\ ^\circ C})$$

Accepted Answer

$$693\ \mathrm{cal}$$

Question 8

Which of the following substances would show the greatest temperature change upon absorbing $$100.0\ \mathrm{J} of $$heat? (Assume each sample is $$10.0\ \mathrm{g})$$

Accepted Answer

Gold ($$\mathrm{S.H.} = 0.128\ \mathrm{J/g\ ^\circ C})$$

Question 9

A diet has a total caloric intake of $$1400\ \mathrm{kcal}. If $$protein provides $$35\% of $$the calories, how many kcal come from protein?

Accepted Answer

$$490\ \mathrm{kcal}$$

Question 10

Which of the following is a chemical change?

Accepted Answer

Tarnishing of silver

Question 11

A sample of P-32 has an initial activity of $$64\ \mu\mathrm{Ci}. $$After $$42.9$$ days, its activity is $$8.0\ \mu\mathrm{Ci}. $$What is the half-life of P-32?

Accepted Answer

$$14.3\ \mathrm{days}$$

Question 12

Which type of radiation has the highest energy?

Accepted Answer

$$\gamma-$$rays

Question 13

What is the product from the alpha decay of $$^{235}_{92}\mathrm{U}$$?

Accepted Answer

$$^{231}_{90}\mathrm{Th}$$

Question 14

Nitrogen-17 ($$^{17}_{7}\mathrm{N}) $$undergoes beta decay ($$^{0}_{-1}\mathrm{e}). $$What is the isotope produced?

Accepted Answer

$$^{17}_{8}\mathrm{O}$$

Question 15

Why is it important that radioisotopes used in diagnostic tests have short half-lives?

Accepted Answer

To minimize harmful side effects of radiation

Question 16

When an atom of uranium-235 is bombarded with neutrons and splits into smaller nuclei, producing a great amount of energy, this process is called:

Accepted Answer

Fission

Question 17

In the sun, nuclei of hydrogen combine to form a larger nucleus and release a great amount of energy. This process is known as:

Accepted Answer

Fusion

Question 18

A patient receives a diagnostic dose of a radioisotope with a half-life of 6 hours. If the initial activity is $$32\ \mathrm{mCi}$$, what will the activity be after 18 hours?

Accepted Answer

$$4\ \mathrm{mCi}$$

Question 19

Which of the following best describes the energy stored in the chemical bonds of a carbohydrate molecule?

Accepted Answer

Potential energy

Question 20

A $$150.0\ \mathrm{g}$$ alloy requires $$59.3\ \mathrm{kJ} to $$raise its temperature from $$298\ \mathrm{K} to$$ $$398\ \mathrm{K}. $$What is the specific heat capacity of the alloy in $$\mathrm{J/g\ ^\circ C}$$?

Accepted Answer

$$3.95\ \mathrm{J/g\ ^\circ C}$$

Exam #1 Practice Questions – Step-by-Step Study Guidance for GOB Chemistry

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