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Azusa Pacific University CHEMISTRY 115 1)Which of the following is a chemical change? Select one: a

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Azusa Pacific University

CHEMISTRY 115

1)Which of the following is a chemical change? Select one:

a.            evaporation of water

b.            melting of copper

c.             tearing paper

d. frying an egg

 

2. The density of ethanol at 20 C is 0.791 g/mL. How many milliliters of ethanol correspond to 12.0 g of ethanol at 20 C?

Select one:

a. 9.49 Ml

 b. 15.2 mL

c. 0.791 ml

d. 30.6 mL

 

 

3. Each of the numbers below is a measured quantity. Solve the calculation and give the correct number of significant figures.           (17.8 x 0.1150) / 6.7

Select one:

a. 0.31

b. 0.3

c. 0.306

d. 0.3055

 

4. A 33.0 g of aluminum is heated on a stove. The temperature of the aluminum increases from 25 C to 120 C. How much heat energy was absorbed? (The specific heat of aluminum is 0.0215 cal/gC.)

Select one:

a. 67 cal

b. 0.0075 cal

c. 0.61 cal

d. 13 cal

 

5. 2.32 g is the same as  . Select one:

a.            232 kg

b.            23.2 cg c. 2320 mg d. 0.0232 dg

 

6. The number 390000, expressed correctly in scientific notation, is          . Select one:

a. 3.9 x 10­6

c. 3.9

 

d. 3.9 x 10-5

 

7. The number 84.3759 rounded to the nearest 1 significant figure is        . Select one:

a.            90

b.            8 c. 80

d. 84

 

8. A patient having a serious reaction caused by a peanut allergy has a doctor’s order to have

0.240 g of epinephrine. The liquid on hand contains 250 mg/5mL bottle. How many milliliters of the liquid are required?

Select one:

a. 4.8 mL

b. 0.0048 mL

c. 12 mL

d. 1.2 mL

 

9. Which of the following explanations is a testable hypothesis? Select one:

a.            A sugar crystal is forming faster because it is grown in cold environment.

b.            A plant is dying because of the direction of spinning of the earth.

c.             A bird lays more eggs because of the intensity of thunderstorms.

d.            A burp increases the weight of a baby.

 

 

10. When aspirin is heated, it melts at 275 F. Convert this temperature into kelvins. Select one:

a. 135 K b. 408 K c. -138 K

d. 375 K

 

11. The energy available by virtue of a rock sitting at the top of a cliff is Select one:

a. chemical energy. b. potential energy.

c. thermal energy.

d. kinetic energy.

 

 

 

 

 

12. Round the following to three significant figures: 399870

Select one:

b. 4.00×106

c. 3.99×105

d. 3.99×106

 

13. The conversion of a solid directly into a gas is called  . Select one:

a.            vaporization

b.            deposition c. sublimation

d. melting

 

14. A weather forecaster predicts that the temperature for the day will reach 88 F. What is the Celsius value for the predicted temperature?

Select one:

a.            88C

b.            273C c. 31C

d. 304C

 

15. Which group contains the alkali metals? Select one:

a.            1A

b.            2A

c.             3A

d.            8A

 

16. Which of the following statements is true about a beta particle? Select one:

a.            it has the same mass as a helium nucleus

b.            when ejected from the nucleus formed has same mass as the original isotope

c.             when ejected from the nucleus of a radioisotope, the nucleus formed has one more proton

d.            it is the same as a gamma radiation

 

17. What is the relationship of a metal atom to the right of another metal atom in the same period? Select one:

a.            The atom to the right is usually the smaller in diameter.

b.            The atom to the right is usually the smaller in atomic weight.

c.             The atom to the right is usually the smaller in atomic number.

d.            The atom to the right is more likely to have fewer isotopes.

 

 

 

 

 

 

18. Most elements have radioisotopes. What is a radioisotope? Select one:

a. An isotope that has a different atomic number. b. An isotope that releases nuclear radiation.

c. An isotope that releases electrical radiation.

d. Any isotope that can absorb nuclear particles.

 

19. Iron-59 has a half-life of 45 days. How much of a 50.0-gram sample would remain after 180 days?

Select one: a. 1.00 g

b. 3.13 g

c. 25.0 g

d. There is no way to determine the results.

 

 

20. 650. J is the same amount of energy as           . Select one:

a.            2720 cal

b.            650. cal c. 155 cal

d. 2.72 cal

e. 1550 cal

 

21. Gamma rays require a thick slab of concrete or lead to block them because they Select one:

a.            have the lowest energy.

b.            are so energetic that they have a very high penetrating power.

c.             are large in size.

d.            are small in size.

 

22. The periodic table of the elements does not list whole numbers for atomic weights. Why? Select one:

a.            The atomic weights are not predictable.

b.            The atomic weights include protons and neutrons at 1 amu each, but they also include electrons, which weigh a lot less than one.

c.             The atomic weight is the weighted average of the masses of the known isotopes of an element.

d.            The atomic weights do not include isotopes.

 

 

 

23. The atomic number is Select one:

a. the number of neutrons in an atom. b. the number of protons in an atom.

c. the number of protons and neutrons in an atom.

d. the number of subatomic particles in an atom.

 

24. Atomic number and mass number differ in that atomic number is the number of       and mass number is        in an atom’s nucleus.

Select one:

a.            protons/the number of neutrons

b.            neutrons/the number of protons

c.             protons/the number of electrons

d.            protons/the sum of protons and neutrons

 

25. The atom’s structure characteristically has Select one:

a.            the protons and neutron within the nucleus.

b.            the electrons located outside the nucleus.

c.             mostly empty space.

d.            All of these choices are correct.

 

26. How many carbon(C) atoms are present in 30 moles of carbon? Select one:

a. 1.20 x 101C atoms

c. 3.60 x 102 C atoms

d. 6.02 x 1023  C atoms

 

27. An alpha particle is identical to which of the following? Select one:

a.            the nucleus of a hydrogen atom

b.            an electron

c.             a beta radiation

d.            the nucleus of a helium-4-atom

 

28. An isotope of sodium contains 11 protons and 12 neutrons. Select one:

a.            The atom also contains 11 electrons.

b.            The atom also contains 12 electrons.

c.             The atom also contains 23 electrons.

d.            There are no other factors related to the 11 protons and 12 neutrons.

 

29. A sample of magnesium weighs 10 grams. How many moles of magnesium are there in the sample?

Select one:

a.            10 moles

 

b.            6 x 1023  moles

c.             60 x 1023  atoms d. 0.4 moles