Exam 1 Spring 17 Answer · Exam 1 Spring 2017 Page 1 of 12 Exam 1 Spring 17Answer 1. (6 pt)...

Exam 1 Spring 2017 Page 1 of 12

Exam 1 Spring ‘17Answer

1. (6 pt) Classify each of the following as an element [E], a compound [C] or a

mixture [M]

a) m muddy water that settles on standing

b) m A filtered cup of coffee, no cream, no sugar

c) m fruit salad (mango, pineapple, and oranges)

d) m Chocolate Chip Cookie

e) c Salt (NaCl)

f) mA bowl of beef noodle soup

g) e Aluminum foil

h) eLiquid bromine

Whosians have come to visit. They are from the planet Choralorafax. Their diet

consists of fruits and berries, and chocolate. Explain the difference between an element,

a compound, and a mixture to the Whosians. Choose something to eat from the list

above for them to eat.

Elements are the building blocks of matter. They consist of a single type of atom. We have elements (not many) in our homes, and I am not talking about elements of style. Aluminum foil made from a block of aluminum that is pressed to a desired thickness. A compound is a substance composed of more than one type of atom, like NaCl. Molecules are made when two or more atoms combine to form a substance using strong attractive forces. Bromine is an element, and a molecule. A mixture is composed of two or more different types of matter that can be separated by physical means into their individual components. Fruit salad is a mixture because it has different kinds of fruit that can be manually separated. The Whosians should eat the fruit salad and can have a chocolate chip cookie if they pick out the chocolate..

2. (3pt) Answers the questions below.


a) (1 point) What is the length of the block if the ruler reads in centimeters?

(it is cut off because it won’t all fit on the page). Answer: The length of the

board is 11.65 ±0.01cm. The edge of the

board in between the 0.6 and 0.7 mark.

We can read this to the millimeter

mark.

b) (1 point) The pressure gauge

reads pressure in psi (pounds per square inch).

How many significant figures are there in this

measurement? You can read this to 4.3 plus a

guess. This means there are three significant

figures for the answer.

c) (4 point) Burt (A), Ernie (B), Kermit (C), and

Gonzo (D) enter a dart contest. The prize is an all-

expense paid trip to Sesame Street . Help the

judges determine the winner by explaining the

difference between precision and accuracy so they

can pick the most accurate AND the most precise

contestant.

Accurate: Accurate values are close to a true or accepted value. Generally, accurate

measurements also have good precision.

Precise: Precise values are grouped close together but are not necessarily accurate.

Athough Erin is precicese because he has a good grouping of darts, he is far from the

bulls eye. Gonzo is the clear winner being both precise and accurate, with good

grouping and being close to the bulls eye.


3. (6 pt) Which of the following is a chemical property of quinine and which is a

physical property of quinine? Use [C] for chemical and [P] for physical

a) P_It has a bitter taste.

b) P_It does not readily dissolve in water.

c) C is thought to bind to (react with) the DNA of a cell infected with

Plasmodium falciparum, the malaria bug, inhibiting the cell’s ability to

replicate.

d) P It melts at 57°C

e) P_It is a white crystalline solid in pure form at room temperature.

f) P It has a molecular mass of 324.417 g/mol

g) _ C Quinine yields carbon dioxide and water vapor when combusted.

h) C When quinine decomposes, it emits toxic fumes of nitrogen oxides.

i) Distinguish between a physical and chemical property in one or two

sentences.

Physical properties are properties that:

1) Do not change the matter, so no chemical bonds are broken.

2) Based on appearance, like taste smell, crystalline shape.

Chemical properties:

1) Involve breaking chemical bonds. The product does not, in anyway, resemble

the reactant.

2) Are inherent to the material and the way the matter reacts with other matter.

These are characteristic changes of that matter during a chemical reaction.

https://en.wikipedia.org/wiki/Gramhttps://en.wikipedia.org/wiki/Mole_(unit)


4. (3 pt) Indicate the number of significant figures in each of the following

measured quantities:

a) 8.1441 mg 5

b) 0.00050 m2 2

c) 6,480,100 s 5

d) —15.20°C 4

e) 10.0800 x 10–2cg 6

f) 0.000 000 654 123n sec 6

5. (4 pt) These values are not written in the most appropriate metric prefix. (All

answers must have a metric prefix) Re-write them please. Show the math and

reasoning you used to support your answer.

a) 6.712 8 X 10—9 Tm (Tera= 1012)

6.712 8𝑥10−9𝑥

1012𝑚

1𝑇𝑚𝑥

1𝑘𝑚

103𝑚= 6.7128𝑘𝑚

b) 8.965 561 X 108 pmol

8.965 561𝑥108𝑝𝑚𝑜𝑙𝑥

10−12𝑚𝑜𝑙

1𝑝𝑚𝑜𝑙𝑥

1𝑚𝑚𝑜𝑙

10−3𝑚𝑜𝑙= 0.8965 561𝑚𝑚𝑜𝑙

c) 816.543 65 X 1012 dm2

816.543 65𝑥1012𝑑𝑚2𝑥

(10−1𝑚)2

𝑑𝑚2𝑥

(𝑀𝑚)2

(106𝑚)2= 8.165 436 5𝑀𝑚

6. (5 pt) Two isotopes of element X occur in nature: isotope 1 has a mass of

190.961amu and an abundance of 37.30% while isotope 2 has a mass of

192.963amu and an abundance of 62.70%. Find the atomic mass of the element.

190.961amu x0.373 0 + 192.963amu x 0.627 0 = 192.2 amu


7. (6 pt) Perform the following calculation and report your answer with the correct

significant figures, scientific notation, and units.

a) (1pt) 100.617 82 g —0.832 17 g + 22.156 1 g + 21.826 g

143.768g

b) (2pt) 2.156 934 51 X 1090 °C + 2.314 276 9 X 1091 °C + 2.95 468 X 1093 °C

3.20768 X1093°C

c) (1pt) [1023 X 10-16]/[1018 X 1082]

10—93

d) (2pt) (0.003 69g)+(6.577 X10—6g)+(8.234X10—4g)

(6.967 7X10—5mL)+(0.000 256 7mL)

13.8g/mL

8. (2 pts) A student measuring the temperature of water mixed with salt, reported a

change of—23°C. What is this temperature change in kelvins?

Celsius and kelvin have the same degree change. means that 1°C = 1K. A change of

—23°C is 23K.


9. (6 pt) An antacid tablet weighing 0.853-g contained calcium carbonate as the

active ingredient, in addition to an inert binder. When an acid solution weighing

56.519 g was added to the tablet, a solution was created and carbon dioxide gas

was released, producing a fizz.

a. If all the carbon dioxide was released in the reaction, and the resulting

solution weighed 57.152 g, how many grams of carbon dioxide were

released? [You do not need a balanced equation, gas law information,

or formulas for this problem]

Mass of reactant must equal the mass of the product.

Mass of the reactant = 0.853g + 56.519 g

Mass of the product = 57.152 g

The mass of the product is clearly lighter than the mass of the reactant. What is the

mass difference? The mass of the carbon dioxide that was lost. 0.220g CO2

b. In terms of Dalton’s postulates, what does this prove?

This is an example of Conservation of Matter. The law states that the mass of

substances in a closed system will remain constant irrespective of the processes

acting on that matter. We extend that to “matter can not be created or destroyed in a

chemical process”. This means mass must be conserved, even if the system is open.

10. (7 pt) Balance the following equations, for this question, if the coefficient is

1[one], put that in the line as well. You will lose points if you leave the lines

blank:

a. __4___BCl3 +___1__P4 +___6__H2 ___4__BP + __12___HCl

b. __2__C9H8O4 + __18__O2 __8__H2O + __18__CO2

c. __2__C2H3Cl + __5__O2 __4__CO2 + __2__H2O + __2__HCl


11. (9 pt) Give the atomic symbol and name for each of the following:

a. A transition element in the 4th period with an even atomic number

divisible by 4.

Cr, Chromium or Ni, nickel

b. The halogen that is a solid.

I, iodine

c. The main group (representative) element in the third period and 5th

group

P, phosphorus

d. An alkali metal in the fifth period

Rb, rubidium

e. An alkaline earth metal in the third period

Mg, magnesium

f. One of the seven diatomic molecules that is a gas at room temperature.

N, nitrogen; O, oxygen; F, fluorine; Cl, chlorine; H, hydrogen

g. A metalloid that has similar properties to carbon

Si, silicon or Ge germanium

h. The name of an allotrope of carbon [the allotropes of carbon have the

same symbol]

Graphite or diamond

i. The name of element 92 and the region on the periodic table where

element 92 is found (name of that region-be specific)

U, uranium. Uranium is an actinide metal because uranium is in the section that

starts with Ac, actinium. These are also called INNER transition metals (not just

transition metals).


12. (4pt) The density of aluminum is 2.70 g/cm3. An irregularly shaped piece of

aluminum weighing 40.0 g is added to a 100-mL graduated cylinder containing

exactly 50.0mL of water. To what height in the cylinder will the water level rise

[final volume]?

The initial volume: 50.0mL

The volume of the piece of Al 40.0𝑔

𝑥1𝑚𝐿 𝐴𝑙

2.70𝑔 𝐴𝑙 = 14.8 mL

Total volume will be 50.0mL+14.8mL=64.8 mL

13. (4pt) Complete the following table.

Isotopic

symbol

Atomic

number

Mass

number

Protons

Neutrons

Electrons

Net charge

𝐵511 5 11 5 6 5 0

𝑵𝒂𝟏𝟏𝟐𝟑 + 11 23 11 12 10 1+

𝑪𝒖𝟐𝟗𝟔𝟒 29 64 29 35 29 0

𝑩𝒓𝟑𝟓𝟖𝟐 𝟏− 35 82 35 47 36 1-

Use this space for scratch for this problem


14. (6 pt) In Chapter 2, we studied the basic architecture of the atom. Answer the

following by identifying the true and false statements. Correct the false

statements and make then true. Use a complete sentence for full credit.

CORRECTING THE STATEMENT MEANS CROSSING OUT THE WORD

THAT MAKES THE STATEMENT FALSE AND ADDING INFORMATION

TO MAKE IT TRUE.

Example: Red and yellow make blue.

Good: Red and yellow make orange. This tells me I should hire you to paint

my house orange, given samples of the rainbow as a choice for paints.

Bad: Red and yellow do not make blue. I can’t tell from this answer if you

know your colors and need to read “Color Kittens”.

a) [T] [F] The atomic mass number indicates the number of electrons and neutrons.

The atomic mass number indicates the number of electrons and protons

b) [T] [F] Milikan determined the charge to mass ratio of the electron.

JJ Thompson determined the charge to mass ratio of the electron.

c) [T] [F] The electron and the proton have about the same mass to three significant

figures, 1.00 amu.

The neutron and the proton have about the sam mass to three significant figure, 1.00

amu.

d) [T] [F] The charge of the electron and the neutron are equal but opposite in sign.

The charge of the electron and the proton are equal but opposite in sign.

e) [T] [F] Isotopes have the same number of neutrons and a different number of

protons

Isotopes have the same number of protons and a different number of neutrons

f) [T] [F] The electron has most of the mass and the electron comprises the volume of

the atom.

The nucleus has most of the mass and the electron comprises the volume of the atom.


15. (3pt) Bismuth melts at 544.5K and boils at 2,140K.

a. Is bismuth a solid, liquid, or a gas at 325.76K

b. Is this an intensive or extensive property? Explain

c. Explain your choice for the phase of bismuth at 325.76K.

Bismuth is a solid at 325.76K. This temperature is below the melting point. Material

below the melting point is in the solid phase, in-between the melting and boiling

points is in the liquid phase, and above the boiling point is in the gas phase.

Melting points and boiling points are independent of the amount of material, and are

an example of an intensive property. Temperature is independent of the amount of

material while heat is dependent on the amount of material.

16. (4 pt) Captain Cody and his Stratosphere Commandos protected our world from

flesh eating Zombies from another planet during the 1950's. He patrolled the

stratosphere every week. If the stratosphere where he roamed is 20.0 mi above

sea level, what is this height in km?

20.0𝑚𝑖

𝑥5,280𝑓𝑡

1 𝑚𝑖𝑥

12𝑖𝑛

1𝑓𝑡𝑥

2.54𝑐𝑚

1𝑖𝑛𝑥

10−2𝑚

1𝑐𝑚𝑥

1𝑘𝑚

103𝑚= 32.2 𝑘𝑚

17. (6 pt) Clarify the following confusing statements using the appropriate units of

either °C, °F or K for temperature, oz., liters, or gal for volume, and inches, ft., or

mi for distance. For each value, only one of the units makes sense. Explain your

choices.

“I was thirsty today. I drank 12 (?) of coke at once. Then I ran 20 (?) in about half a

minute to catch a bus. Inside the bus, it was hot. I think it was 90 (?) because the air

conditioning was not working and people were sweating."

12 oz is a reasonable amount. It is about the size of a coke can or 1 ¼ cup of coke. I

ran 20ft in about 30 seconds. The average stride is about 2ft, a distance too short to

run and be winded after 30sec, while 20 mi is a distance too long to run in 30 sec. the

temperature in the bus was 90°F, a bit below body temperature (37°C). A temperature

of 90K would be really cold, while a temperature of 90°C would be deadly hot, (you

would be dead for either of these temperatures).


18. (5 pt) In Chapter 2, we are introduced to the periodic table. Answer the

following by identifying the true and false statements. Correct the false

statements and make then true by writing a complete sentence, not crossing out

and repairing the answer.

a) In the modern periodic table, the elements are arranged in order of

increasing number of neutrons [T] [F]

In the modern periodic table, the elements are arranged in order of increasing number

of protons.

b) Elements in periods show similar chemical and physical properties [T] [F]

Elements in families (or groups) show similar chemical and physical properties

c) Elements can be classified as either metalloids or nonmetals. [T] [F]

Elements can be classified as either metals or nonmetals. [I also accepted metals, non

metals, metalloids’

d) Metals are found above the staircase. [T] [F]

Metals are found below the staircase.

e) Silver is a lanthanide element. [T ] [F]

Silver is a transition element

19. (6 pt) A student has the idea of removing a decorative stone sphere from in front

of a campus building. The radius of the sphere is 0.289 ft.; the density of the

stone is 3.52 g/mL

a) What is the mass of the sphere in pounds (lbs)?

b) Is the student likely to walk off with it unassisted? Explain why or why

not. For your reference: The average person weighing about 180 lb should

be able to lift 40-50 lb. An average watermelon has a mass of around 23

lbs. 1 lb = 453.59237 g,

i. Volume of a sphere = (4/3)πr3

Scratch paper provided on next page.

𝑉=

4

3𝜋 (

0.289𝑓𝑡𝑥

12𝑖𝑛

𝑓𝑡𝑥

2.54𝑐𝑚

𝑖𝑛)

3

volume of the sphere 2863 cm3

2863𝑐𝑚3𝑥

1𝑚𝐿

𝑐𝑚3𝑥

3.52𝑔 𝑠𝑡𝑜𝑛𝑒

1𝑚𝐿 𝑠𝑡𝑜𝑛𝑒𝑥

1𝑙𝑏

453.59237𝑔= 22.2𝑔


This mass is less than the mass of the average watermelon, so yes, I think the student

could walk away with it if lifting a watermelon of a similar size is easy for that

person too.

Scratch paper for problem 19

Exam 1 Spring 17 Answer · Exam 1 Spring 2017 Page 1 of 12 Exam 1 Spring 17Answer 1. (6 pt)...

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