Assignment 1 Chemistry

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NAME: Tashana Williams 09/07/2015
CHM 100-601HY Assignment #1
Instructor: Dr. Frank Ramdayal
DUE DATE: 11:30 PM, TUESDAY, SEPTEMBER 8 (Email your answers to
[email protected])
SECTION A - Short answers (39 points)
1)What is chemistry?
-Chemistry is the study of matter and the transformations it undergoes.
2) What is an element?
- An element is a substance that cannot be decomposed by any chemical reaction into
simpler substances.
3) What is a compound?
- A compound is a substance composed of atoms, two or more elements chemically
combined.
4) What is an atom?
-An atom is the smallest unit on an element that has the properties of that element, both
physical and chemical properties.
5) What is a molecule?
- A molecule is made of up of two or more atoms chemically combined.
6) Does each of the following statements describe physical or chemical properties, indicate?
(a) Oxygen gas supports combustion.

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- a. Chemical properties, change in heat energy.
(b) Water boils below 100
0
C on top of a mountain.
- b. Physical properties, H2O is still H2O.
(c) Lead is denser than Aluminum.
- c. Physical properties, lead is 4 times denser than aluminum. Lead atoms are bigger.
(d) Rain water in industrialized regions tends to be acidic.
- d. Chemical properties, chemicals in the air produce acids, changing the composition and
identity of the water.
7) Does each of the following statements describe a chemical or physical change, indicate?
(a) The helium gas in a balloon tends to leak out after a few hours.
- a. Physical change, gas still the same, the balloon still the same.
(b) The growth of plants depends on the sun’s energy in a process called photosynthesis.
- b. Chemical change, plant sun is turning carbon dioxide and water into oxygen and
carbohydrates.
(c) A spoonful of cooking salt dissolves in water.
-c. Chemical change, the sodium bonds are broke and replaced with water.

(d) When an electric current is passed through water, hydrogen gas and oxygen gas are
produced.
- d. chemical change, the hydrogen and oxygen water molecules have now become gases
H2 and O2.

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8) Classify each of the following as an element, compound, homogenous mixture or
heterogeneous mixture.
(a)Filtered air (b) C6H12O6
a. Homogenous mixture b. Compound
(c) O3 (d) Blood
c. element d. heterogenous mixture
SECTION B - Multiple choice (31) points
Each question below has one correct answer. Choose the letter, A, B, C or D corresponding
to the correct answer and email that answer to me together with your answers from part
"A". Please ensure that each question is numbered correctly and you have the
letter of the answer you choose, next to the number of that question.
9). Water (H2O) and carbon dioxide (CO2) are produced in a chemical reaction when methane
(CH4 ) and oxygen (O2 ) are combined and heated. Which are the reactants and which are the
products?
A. CH4 and O2 are reactants; H2O and CO2 are products
B. CH4 and H2O are reactants; O2 and CO2 are products
C. H2O and CO2 are reactants; CH4 and O2 are products
D. H2O and O2 are reactants; CH4 and CO2 are products
- a. CH4 and O2 are the reactants; H2O and CO2 are products.
10) What, if anything, is wrong with the following chemical reaction?
Cl2 (g) + Br2 (l) 2HCl(g) + 2HBr(g)

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A. It is not a chemical reaction but only a physical transformation.
B. The products include elements not in the reactants.
C. All of the compounds are not gases.
D. There is nothing wrong with the chemical reaction.
-B. The products include elements not in the reactants.
11) A generalization that concisely summarizes the outcome of a series of experiments is
describing a:
A. Hypothesis
B. Law
C. Theory
D. Problem
- B. Law
12) Another name for a homogeneous mixture is:
A. Pure substance
B. A solution
C. Compound
D. Matter
- B. A solution
13) Which of the following is a pure substance in a heterogeneous state?
A. Aluminum can
B. Ice water
C. Salt water
D. Glucose
- B. Ice water

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14) Which of the following is an example of a solution?
A. Blood
B. Salt water
C. Marble
D. Gold
- B. Salt water
15) I have a substance that has a melting point of –23°C and a boiling point of 17°C. What
state will it exist in at room temperature? (23°C)
A. Solid
B. Gas
C. Liquid
D. Cannot tell
- B. Gas
16) When water is heated above its boiling point, what will its molecular formula be?
A. H2 and O2
B. H2O
C. It will change to steam, H2O2.
D. It will change to steam, H4O2.
- B. H2O
17) Which of the following statements is correct?
A. A theory is a well-tested hypothesis.
B. A hypothesis is a well-tested theory.
C. A theory cannot be proven wrong.
D. A law often refers to the first time a theory is presented.
- A. A theory is a well-tested hypothesis.
18) Which of the following is a chemical change?
A. Sugar dissolving in water.

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B. Ice melting to produce liquid water
C. An iron nail rusting when left in air.
D. Dry ice (solid carbon dioxide) sublimes at room temperature and pressure.
- C. An iron nail rusting when left in air.
19) Which of the following is not a compound?
A. Sulfur dioxide (SO2)
B. Ammonia (NH3)
C. Mixture of O2 gas and N2 gas
D. Carbon monoxide (CO)
- C. Mixture of O2 gas and N2 gas
20) Any material that is made up of only one type of atom is classified as:
A. A solution
B. An elemental substance
C. A compound
D. A heterogeneous mixture
- B. An elemental substance
21) The periodic table lists:
A. Fewer than 100 elements
B. More than 100 elements
C. More than 100 compounds
D. Thousands of atoms, ions, and molecules
- B. more than 100 elements

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22) Molten iron cooling to solid iron is an example of:
A. Sublimation
B. Condensation
C. Freezing
D. Melting
- C. Freezing
23) Which of the following is a physical change?
A. Frying an egg.
B. Ice melting to produce liquid water.
C. An iron nail rusting when left in air.
D. Burning charcoal in air.e4
- B. Ice melting to produce water.