Louisiana College

CHEM MISC

Midterm Exam

Question1)Accuracy tells us how close a measurement is to the true value.

True

False

 

 

Question 2

Round the following to three significant figures:

 

399870

 

a. 3.99×106

 

b. 4.00×106

 

c. 4.00×105

 

d. 3.99×105

 

 

Question 3

Which of the following explanations is a testable hypothesis?

 

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.

 

 

Question 4

 

The energy available by virtue of a rock sitting at the top of a cliff is

 

a.          chemical energy.

 

b.          potential energy.

 

c.          thermal energy.

 

d.          kinetic energy.

 

 

Question 5

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?

a. 4.8 mL

 

b. 0.0048 mL

 

c. 12 mL

 

d. 1.2 mL

 

 

Question 6

A container holding a mixture of ice and water is placed in a 115 C oven. The ice- water mixture rises in temperature until all the ice has melted away.

True False

 

Question 7

2.32 g is the same as     .

 

a.          232 kg

 

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

 

 

 

Question 8

 

The conversion of a solid directly into a gas is called       .

 

a.          vaporization

 

b.          deposition c. sublimation

d. melting

 

 

Question 9

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

 

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

d. 375 K

 

 

Question 10

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?

a. 9.49 mL b. 15.2 mL c. 0.791 ml

d. 30.6 mL

 

 

Question 11

The number 84.3759 rounded to the nearest 1 significant figure is          .

 

a.          90

 

b.          8 c. 80

d. 84

 

 

Question 12

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

a. 3.9 x 10-6

 

b. 3.9 x 105

 

c. 3.9

 

d. 3.9 x 10-5

 

 

 

 

Question 13

 

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

a.          88C

 

b.          273C c. 31C

d. 304C

 

 

Question 14

Each of the numbers below is a measured quantity. Solve the calculation and give number of significant figures.

(17.8 x 0.1150) / 6.7

 

a. 0.31

 

b. 0.3

 

c. 0.306

 

d. 0.3055

 

 

Question 15

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.)

a. 67 cal

 

b. 0.0075 cal

 

c. 0.61 cal

 

d. 13 cal

 

 

Question 16

The higher the temperature of something, the greater the kinetic energy of the particles from which it is made.

Select one:

 

True False

 

Question 17

Which of the following is a chemical change?

 

a.          evaporation of water

 

b.          melting of copper

 

c.          tearing paper d. frying an egg

 

 

 

Question 18

 

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

a. 1.00 g

 

b. 3.13 g

 

c. 25.0 g

 

d.          There is no way to determine the results.

 

Question 19

 

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

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.

 

 

Question 20

The mass in grams of one mole of an element is the element’s                                 . Select one:

1. atomic number

2. atomic weight

 

3. molar mass

 

4. isotope number

 

Question 21

 

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

1. An isotope that has a different atomic number.

 

2. An isotope that releases nuclear radiation.

 

3. An isotope that releases electrical radiation.

 

4. Any isotope that can absorb nuclear particles.

 

 

Question 22

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

1. 1.20 x 101C atoms

 

2. 1.80 x 1023 C atoms

 

3. 3.60 x 102 C atoms

 

4. 6.02 x 1023 C atoms

 

Question 23

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

1. The atom also contains 11 electrons.

 

2. The atom also contains 12 electrons.

 

3. The atom also contains 23 electrons.

 

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

 

 Question 24

Trace elements and vitamins are required for the body to function properly

Select one:

 

True False

 

Question 25

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

1. have the lowest energy.

 

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

 

3. are large in size.

 

4. are small in size.

 

 

Question 26

The atom’s structure characteristically has

Select one:

 

1. the protons and neutron within the nucleus.

 

2. the electrons located outside the nucleus.

 

3. mostly empty space.

 

4. All of these choices are .

 

Question 27

The emission of an alpha particle only decreases the atomic mass of the atom. Select one:

True False

 

 Question 28

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

1. the nucleus of a hydrogen atom

 

2. an electron

 

3. a beta radiation

 

4. the nucleus of a helium-4-atom

 

Question 29

The isotope of hydrogen that is a radioisotope has a mass number of 3. Select one:

True False

 

Question 30

Which group contains the alkali metals? Select one:

1. 1A

2. 2A

 

3. 3A

 

4. 8A

 

Question 31

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:

1. protons/the number of neutrons

 

2. neutrons/the number of protons

 

3. protons/the number of electrons

 

4. protons/the sum of protons and neutrons

 

 Question 32

The atomic number is

Select one:

 

1. the number of neutrons in an atom.

 

2. the number of protons in an atom.

 

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

 

4. the number of subatomic particles in an atom.

 

Question 33

What is the relationship of a metal atom to the right of another metal atom in the same period?

Select one:

 

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

 

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

 

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

 

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

 

Question 34

 

Which of the following statements is true about a beta particle?

 

 

Select one:

 

1. it has the same mass as a helium nucleus

 

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

 

3. when ejected from the nucleus of a radioisotope, the nucleus formed has one more proton
4. it is the same as a gamma radiation

 

Question 35

650. J is the same amount of energy as                                        .

 

 

Select one:

 

1. 1550 cal

 

2. 155 cal

 

3. 2720 cal

 

4. 2.72 cal

 

5. 650. cal

 

Question 36

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

 

 Question 37

According to the octet rule, how many valence electrons are present in a chloride ion (Cl-)?

Select one:

 

1. 1

 

2. 2

 

3. 8

 

4. 4

 

Question 38

What is the molar mass of magnesium chloride? Select one:

1. 59.80 g/mol

 

2. 90.40 g/mol

 

3. 95.30 g/mol

 

d. 125.90 g/mol

 

 Question 39

Which of the following atom pairs would most likely be connected by an ionic bond?

Select one:

 

1. K and Br

 

2. O and Br

 

3. S and Br

 

4. F and Br

 Question 40

The difference between an ionic bond and a covalent bond is that Select one:

1. ionic bonds commonly occur between two metals and covalent bonds occur between metals and nonmetals.
2. ionic bonds are between atoms that can share electrons; covalent bonds are between atoms that will donate/accept electrons.
3. covalent bonds come about because of a sharing of electrons; ionic bonds do not.
4. ionic bonds are between smaller atoms; covalent bonds are between large atoms.

 

 

 

 

Question 41

Potassium and magnesium cannot form a binary compound together. Select one:

True False

 

 Question 42

Which of the following atom pairs would most likely be connected by a covalent bond?

Select one:

 

1. Na and O

 

2. O and Cl

 

3. Na and Cl

 

4. K and F

 

 Question 43

The formula of calcium sulfate is             . Select one:

1. CaSO3

 

2. CaSO4

 

3. CaS

 

4. CaS2

 Question 44

Which ion has the same number of electrons as the noble gas argon? Select one:

1. F-

 

2. Mg2+

 

3. Br-

 

4. Ca2+

 

 Question 45

The formula weight of magnesium fluoride is 62.30 amu. Select one:

True False

 

 

Question 46

What is the mass of 0.00142 mole of vitamin C (C6H8O6)? Select one:

a. 0.250 g

 

b. 0.500 g

 

c. 0.125 g

 

d. 2.50 g

 

 

 

 

Question 47

A 1.0 x 102- gram sample is found to be pure alanine, an amino acid found in proteins. How many moles of alanine are in the sample?

 

 

Select one:

 

1. 0.20 moles

2. 0.90 moles

 

3. 1.1 moles

 

4. 890 moles

 

 Question 48

What is the molar mass of isopentyl acetate, C7H14O2, a compound responsible for the odor of bananas?

Select one:

 

1. 130.19 g/mole

 

2. 98.32 g/mole

 

3. 146.58 g/mole

 

4. 119.35 g/mole

 

5. 13.19 g/mole

 

Question 49