Part 1 of 4 - 8.0/ 8.0 Points
Question 1 of 12
4.0/ 4.0 Points
Which statement below can best be classified as a scientific law?
Correct A.Within a certain distance from each other, objects with a small mass accelerate towards an object with a larger mass.
B.The moon travels around the Earth at a high speed.
C.Life on earth likely began around 3.5-4 billion years ago.
D.sugars are made of carbon, hydrogen, and oxygen atoms
E.none of the above could be considered a law
Answer Key: A
Feedback: Good! A law must synthesize past observations and predict future ones.
Question 2 of 12
4.0/ 4.0 Points
Who discovered the atomic theory?
A.Antoine Lavoisier
Correct B.John Dalton
C.John Dalton and Antoine Lavoisier
D.Albert Einstein
E.none of the above
Answer Key: B
Feedback: Good! It was Dalton.
Part 2 of 4 - 12.0/ 12.0 Points
Question 3 of 12
4.0/ 4.0 Points
3.21 × 10-3 written as a decimal is:
A.0.321
Correct B.0.00321
C.3.21
D.0.000321
E.none of the above
Answer Key: B
Feedback: Good. Scientific notation is discussed in section 2.2 of the text.
Question 4 of 12
4.0/ 4.0 Points
Express 0.0045 m in scientific notation.
A.0.45 × 104 m
B.4.5 × 104 m
C.4.5 × 10-4m
D.4.5 × 103m
Correct E.4.5 × 10-3 m
Answer Key: E
Feedback: Good. Scientific notation is discussed in section 2.2 of the text.
Question 5 of 12
4.0/ 4.0 Points
`The correct number of significant figures in the number 1.2501 is:
A.7
Correct B.5
C.4
D.ambiguous
E.none of the above
Answer Key: B
Feedback: Good. Sig figs are discussed in section 2.3 of the text.
Part 3 of 4 - 20.0/ 20.0 Points
Question 6 of 12
4.0/ 4.0 Points
`Which of these is a pure substance?
Correct A.water
B.sand
C.chocolate chip cookie
D.air
E.none of the above
Answer Key: A
Question 7 of 12
4.0/ 4.0 Points
____ energy is the energy of position.
A.electrical
B.kinetic
Correct C.potential
D.chemical
E.none of the above
Answer Key: C
Question 8 of 12
4.0/ 4.0 Points
`Which of the following items is a mixture?
A.sodium
B.glucose
C.diamond
Correct D.steel
E.none of the above
Answer Key: D
Question 9 of 12
4.0/ 4.0 Points
`Suppose I wanted to increase the temperature of H2O from 30.0 C to 55.0 C. How much heat in kJ would I need to add to a 100.0 g sample of H2O to acheive this?
A.0.598
B.10450
C.1.05
Correct D.10.5
E.none of the above
Answer Key: D
Question 10 of 12
4.0/ 4.0 Points
`A solid that does not have a long range repeating order is called ________.
A.fixed
B.rigid
Correct C.amorphous
D.crystalline
E.none of the above
Answer Key: C
Part 4 of 4 - 10.0/ 10.0 Points
Question 11 of 12
5.0/ 5.0 Points
`When I was recently living in Sweden, the cost of gasoline was about 16.00 kr per liter. The most I could pump to fill up the empty tank on my Volvo v70 was 350 kr worth of gas at a time, after which amount the gas pump would shut off. This 350 kr worth of gas would last for about 190 km. (A) Given that the currency exchange rate was $1.00 = 6.00 kr, what was the cost of gasoline in dollars per gallon? (B) What was my gas mileage (fuel efficiency) in miles per gallon?
All work must be shown, labeled, and explained in detail to receive credit. Note that where applicable, superscripts (X2) can be written as X^2 and subscripts (X2) can be written as X_2 if it saves you time.
a.) Cost of gas in U.S. dollars/gal: $0.70/gallon
Variables: 1 gallon = 3.785 L, 1 usd = 6.00 kr
16 kr/L * 1gal/3.785L = 4.23 kr/gal
4.23 kr/gal * 1 usd/6.00 kr = 0.705 usd/gal
Using the rules of rounding, 0.705 would round the five up if there were other variables behind it, however there are none, and the zero is even, so it remains rounded at 0.70.
b.) Gas mileage in miles/hr
Variables: 1 km = .621 miles, 1 gal = 3.785 L
350kr/16.00kr/L = 21.875L of fuel in the tank.
21.875L * 1gal/3.785L = 5.78 gallons in tank
190km/5.78 gal * 0.621 miles/1km = 20.41 miles per gallon
Feedback: See conversions in Chapter 2
Comment: Perfect ...way to rock this!
Question 12 of 12
5.0/ 5.0 Points
`The general public's definition of "theory" does not match the scientific definition of "theory." For example, non-scientists often say, "But it's JUST a theory!" What is wrong with this line of thinking? What is implied by this statement, and how does it reflect an improper definition of the term? What word from the course material thus far may perhaps be a better choice for the general public to use here instead of the word "theory"?
When people say "It's just a theory" they are mistaken about the definition of the word theory. From our reading, I learned that theories are as close to the truth as you can get to explaining our observations and proposed laws. Well established theories are what the majority of our science knowledge is based off of. They have been tested, put through the wringer, tried to be proven wrong, and the outcomes are still the same. If they are proven to be wrong, they go back to the drawing board and try again. Theories are oftentimes referred to as models, such as Dalton's Atomic Theory is a model for atomic structure. So to use the word theory in that statement would be incorrect, because they are well established and mostly proven to be true time and time again.
I think a better word to replace the word theory in that statement would be hypothesis. A hypothesis is synonymous with the word guess to me and would fit better in that statement because it is less established and more open for experimentation to be proven true or false.
Feedback: See section 1.4
Comment: Perfect
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