Wednesday, July 1, 2020

Chemistry UNIT 1 - Practice Assessment


1. Which branch of chemistry is concerned with the detection or identification of substances present in a sample and their amount?

a) analytical chemistry
b) organic chemistry
c) inorganic chemistry
d) physical chemistry
e) biochemistry

2. Identify the INCORRECT statement below:

a) Potential energy is the energy an object possesses because of its position, condition, or composition.
b) Energy is defined as the capacity to do work or to transfer heat.
c) Liquids flow and assume the shape of their container, occupying all available volume.
d) Endothermic processes absorb energy from their surroundings.
e) Chemical properties are related to the kinds of chemical reactions that substances undergo as they change composition.

3. Which of the following properties of Na metal is a physical property?

a) Na tends to give up an electron to form ionic compounds.
b) Na has a high electrical conductivity.
c) Na, when dropped into water, causes the evolution of H2 gas.
d) Na reacts violently with oxygen.

4. Which of the following property is NOT an intensive property of a material?

a) density
b) color
c) combustible
d) melting point
e) mass

5. Which of the following materials has NOT been properly classified?

a) Apple juice is a homogeneous mixture.
b) Antimony is an element.
c) A snow cone is a heterogeneous mixture.
d) Steel is a compound.
e) Granite is a heterogeneous mixture.

6. The correct symbol for the element Tin is:

a) Sn
b) Ti
c) Tn
d) Sb
e) W

7. The most abundant element by % mass in the Earth¹s crust, oceans and atmosphere is:

a) Silicon
b) Oxygen
c) Hydrogen
d) Water
e) Iron

8. Which is an INCORRECT statement regarding the SI system of units?

a) The basic unit of mass in the SI system is the gram.
b) The basic unit of length in the SI system is the meter.
c) The basic unit of time in the SI system is the second.
d) The basic unit of volume in the SI system is the cubic meter.
e) The basic unit for amount of substance in the SI system is the mole.

9. The density of Fe is 7.86 g/mL. Convert this to pounds per cubic foot.

a) 0.528
b) 491
c) 76.0
d) 62.9
e) 1.01x108

10. This summer I took a 4500 mile vacation in a van which gets 13 miles/gallon of gasoline. If the average price of gasoline on the trip was $1.27 per gallon, how many dollars did I spend on gasoline?

a) $272
b) $375
c) $143
d) $43
e) $440

11. A reaction requires 10.0 g ethanol. What volume of ethanol/water mixture which is 60% ethanol by mass would be required? The Specific Gravity of this mixture is 0.8937.

a) 6.71 mL
b) 5.36 mL
c) 536 mL
d) 18.6 mL

12. Permalloy steel is an alloy which is 21.2% Fe by mass. How many grams of Fe are present in 1.000 kg of steel?

a) 212 g
b) 21.2 g
c) 0.0212 g
d) 4.7 g
e) 4716 g

13. Which distance is greater? (Given: 1 Ångstroms = 1 x 10-10 m)

a) 5 Ångstroms
b) 1 nm
c) 10-6 mm
d) 100 pm

KEY

1)a 2)c 3)b 4e 5)d 6)a 7)b 8)a 9)b 10)e 11)d 12)a 13)b

1. Identify the INCORRECT statement below:

a) Energy is defined as the capacity to do work or to transfer heat.
b) Gravity is an example of potential energy.
c) The reaction of Mg metal with oxygen to form magnesium oxide is an example of a physical change.
d) Gases and liquids are fluid states of matter.
e) Exothermic processes liberate energy into their surroundings.

2. Which is an INCORRECT statement regarding unit systems?

a) One centimeter is 10-2 meters, and one nanosecond is 10-3 picoseconds.
b) The gram is defined to be the mass of 1 cm-3 of liquid water at 4° C at atmospheric pressure.
c) The basic unit of length in the SI system is the meter.
d) A liter is slightly larger than a quart.
e) A cubic centimeter and a milliliter are the same volume.

3. Which element is INCORRECTLY matched with its symbol?

a) Cu / copper
b) Pb / lead
c) K / potassium
d) Cr / chromium
e) B / bismuth

4. Which of the following property is an intensive property of a material?

a) energy
b) volume
c) density
d) mass

5. Which of the following properties of water is chemical property?

a) Water boils at 100° C under atmospheric pressure conditions.
b) Water reacts violently with alkali metals causing the evolution of H2 gas.
c) Pure water has a very low electrical conductivity.
d) The density of liquid water is slightly higher than that of solid water.

6. Which element below is NOT among the five most abundant elements by % mass in the Earth's crust, oceans and atmosphere?

a) Aluminum
b) Oxygen
c) Silicon
d) Hydrogen
e) Iron

7. Denatured alcohol is ethyl alcohol to which various agents have been added to render it unfit for human consumption. A particular formula of denatured alcohol has 91% ethyl alcohol by mass. How many grams of ethyl alcohol are present in 500 g of this denatured alcohol?

a) 910 g
b) 455 g
c) 4.55 x 104 g
d) 4.7 g
e) 491 g

8. Which of the following materials has NOT been properly classified?

a) Soil is a homogeneous mixture.
b) Bromine is an element.
c) Water is a compound.
d) Steel is a homogeneous mixture.
e) Wood is a heterogeneous mixture.

9. The density of Au is 19.3 g/mL. What would be the value of a 100 cm3 ingot of gold if gold is worth $35 per ounce. (Note: There are 16 ounces in a pound; 1 pound = 0.4536 kg)

a) $ 123
b) $ 68
c) $ 2,383
d) $ 3,500
e) $ 440

10. Which volume is greater? (Given: 1.00 in = 2.54 cm)

a) 2 x 10-2 in3
b) 2 x 10-6 m3
c) 1 cm3
d) 1 x 10-3 L

11. I want to measure out 50 grams of liquid methanol from a bottle on the shelf. The density of liquid methanol is 0.79 g/mL. How many mL do I need to measure out?

a) 79 mL
b) 50 mL
c) 39.5 mL
d) 1.58 x 10-2 mL
e) 63 mL

12. Which branch of chemistry is concerned with, among other things, the energy changes associated with chemical reactions?

a) organic chemistry
b) biochemistry
c) analytical chemistry
d) physical chemistry
e) inorganic chemistry

KEY

1)c 2)a 3)e 4)c 5)b 6)d 7)b 8)a 9)c 10)b 11)e 12)d

1. Which state of matter does not completely fill its container and has no definite shape of its own?

a) gas
b) liquid
c) solid
d) none of these

2. Which state of matter is most easily compressed?

a) gas
b) liquid
c) solid
d) all are the same

3. Which of the following substance classifications is NOT CORRECT?

a) vegetable soup/homogeneous mixture
b) chlorine/element
c) sodium chloride/compound
d) raisin bread/heterogeneous mixture

4. A motorcycle engine has a displacement volume of 650 cubic centimeters (650 cm3). What is the volume in cubic inches?

a) 260 in3
b) 40. in3
c) 11,000 in3
d) 1600 in3

5. An ore is mined in which the cobalt content is 1.2% by mass. How many pounds of ore must be processed to yield 15 pounds of cobalt?

a) 1,250 pounds
b) 1.8 pounds
c) 180 pounds
d) 240 pounds

6. An iodine atom has a diameter of 2.66 x 10-10 m. If iodine atoms are lined up so that they are just touching, how many of them would it take to have a line 1.00 feet long?

a) 3.76 x 109 atoms
b) 7.22 x 1015 atoms
c) 1.15 x 109 atoms
d) 7.70 x 105 atoms

7. Which of the following is a chemical change involving silver?

a) It conducts an electric current.
b) It turns black when exposed to sulfur.
c) It boils at 2212oC.
d) Molten silver freezes at 962oC.

8. Below are five properties concerning a sample of elemental gallium. Which of the following answers specifies all the intensive properties?

I. The temperature of the sample is 18oC.
II. The mass of the sample is 16.2 grams.
III. The volume of the sample is 2.74 cm3.
IV. The density of the sample is 5.9 g/cm3.
V. The sample reacts readily with fluorine.

a) I and IV
b) IV and V
c) II and III
d) I, IV, and V

9. Which of the following is an example of a compound?

a) aluminum
b) sodium bicarbonate
c) air
d) mud

10. The element indium has a density of 7.31 g/cm3. What is the mass of a piece of indium whose volume is 0.52 cm3?

a) 3.8 g
b) 14 g
c) 7.3 g
d) 8.2 g

11. In order to achieve orbit, a rocket has to reach a speed of 5.0 mile/second. What is this speed in kilometers/hour? (1 mile = 5280 feet, 12 in = 1 foot, 1 meter = 100 centimeters, 1 kilometer = 1000 meters)

a) 5800 kilometer/hour
b) 29,000 kilometers/hour
c) 4500 kilometers/hour
d) 18,000 kilometer/hour

12. Which of the following element/symbol combinations is NOT CORRECT?

a) sodium/Na
b) oxygen/O
c) lead/Pb
d) silver/Si

KEY

1)b 2)a 3)a 4)b 5)a 6)c 7)b 8)d 9) b 10)a 11)b 12)d

1. The EPA emission standards limit each automobile exaust to 23.0 g of carbon monoxide (CO) per mile. In an average city there are 82,700 cars, each driven an average 13.5 miles/day. How much CO (in kg) can be legally discharged into the atmosphere each day?

a) 48.7
b) 2.45 x 105
c) 2.57 x 104
d) 141
e) 3.5 x 104

2. Of the following properties of sucrose, which ones are chemical properties?

I. It dissolves in water.
II. When treated with yeast it produces alcohol.
III. It is a white solid.
IV. It has a density of 1.587 g/cm3.
V. Upon heating in air, it turns black and emits a caramel odor.

a) I, IV, and V
b) I and II
c) II and V
d) I, II and IV
e) III and IV

3. Which branch of chemistry deals with determining the identity and composition of matter?

a) analytical
b) organic
c) physical
d) biochemistry
e) inorganic

4. Which of the following processes are exothermic?

I. Combustion of natural gas.
II. Freezing water.
III. Melting ice.
IV. Boiling water.
V. Condensing steam.

a) III, IV and V
b) I, II, and III
c) III and IV
d) I, II and V
e) all of them

5. Which of the following properties would not be useful in charecterizing a substance?

a) density
b) shape
c) color
d) melting point
e) tendency to burn

6) Which of the following statements is FALSE?

a) Different mixtures of the same substance can have different compositions.
b) Compounds are composed of two or more elements in fixed proportions.
c) A solution is a homogeneous mixture.
d) Elements cannot be decomposed into simpler substances by chemical means.
e) A heterogeneous mixture has a constant composition throughout.

7. Which of the following materials is NOT a pure substance?

a) ethyl alcohol
b) salt
c) aspirin
d) iron
e) cheese

8. In Biblical times, volume was measured by the OMER and weight by the SHEKEL. Given the conversions below, calculate the density of gasoline (0.680 g/mL) in sheckels/omer.

1.00 sheckel = 14.1 g 1.00 omer = 3.964 L

a) 12.2
b) 82.2
c) 38.0
d) 191
e) 0.242

9. Nichrome is an alloy (mixture) commonly used to make heating elements. It is composed of 60% nickel, 24% iron and 16% chronium. If you have 2.15 g of nichrome wire, how much of each element do you have?

a) 1.6g Ni, 0.31g Fe, 0.24g Cr
b) 1.6g Ni, 0.41g Fe, 0.14g Cr
c) 1.3g Ni, 0.52g Fe, 0.34g Cr
d) 1.2g Ni, 0.61g Fe, 0.14g Cr
e) 1.3g Ni, 0.41g Fe, 0.43g Cr

10. The same amount of heat is added to a 25 g sample of each of the metals below. If they are all initially at 25oC, which will reach the highest temperature?

a) nickel, msp.ht. = 0.444 J/goC
b) beryllium, sp.ht. = 1.82
c) calcium, sp.ht = 0.653
d) copper, sp.ht = 0.385
e) gold, sp.ht = 0.129

11. The density of octane is 0.702 g/mL. What is the volume of 63.0 g of octane?

a) 84.7 mL
b) 89.7 mL
c) 45.6 mL
d) 22.5 mL
e) 108 mL

12. The statement that the total mass does not change in a chemical reaction is the Law of:

a) Conservation of Matter
b) Definite Proportions
c) Evolution
d) Greatest Simplicity
e) Thermodynamics

13. From the decomposition of an unknown solid, one obtains a gas and a new solid, both of which are pure substances. From just this information it can be said, without a doubt, that:

a) one of the products is an element
b) neither product is an element
c) both products are elements
d) the original solid is not an element

14. Which of the following properties do liquids and gases have in common?

a) they expand slightly on heating
b) they will flow
c) they are rigid
d) they are easily compressed
e) they expand to fill their container

15. The fact that compound calcium carbonate is made up of 40% calcium, 12% carbon, and 48% oxygen is an illustration of the Law of:

a) Constant Composition
b) Conservation of Matter and Energy
c) the Jungle
d) Multiple Proportions
e) Transmutation

KEY

1)c 2)c 3)a 4)d 5)b 6)e 7)e 8)d 9)c 10)e 11)b 12)a 13)d 14)b 15)a