Question 5 of 32
3.0/ 3.0 Points
`I was wading in the creek and discovered what I thought to be a small meteorite. I took a small
sample of it home, ran some fancy schmancy chemical tests on it, and determined it was
...
Question 5 of 32
3.0/ 3.0 Points
`I was wading in the creek and discovered what I thought to be a small meteorite. I took a small
sample of it home, ran some fancy schmancy chemical tests on it, and determined it was 18.0%
chromium by mass. How many grams of this meteorite would I need to be able to have 15.0 g of
chromium?
A. 100
B. 120.0
C. 2.7
D. 83.3
Feedback: Great! Mass percent discussed in Chapter 6.2.
Question 6 of 32
3.0/ 3.0 Points
Since 1983, pennies have been made with zinc and plated with copper. Prior to 1983, pennies
were about 95% copper and 5% tin and zinc. However, from 1793-1837, pennies were pure
copper. If you had a penny from 1800 that had a mass of 2.78g, how many atoms of copperwould you have?
A.
8.13 × 10-26
B.
1.67 x 1024
C.
2.63 × 1022
D.
1.19 × 1026
E.6.02 × 1023
Feedback: Great! Mass percent discussed in Chapter 6.2.
Question 7 of 32
3.0/ 3.0 Points
In the research lab, I have finally done it! I've discovered a new compound! I have determined
that its empirical formula, but in order to determine its actual molecular formula, I need to know
which of the following?
A. the number of moles of the compound in a 1.00 g sample of the substance
B. the density of the compound
C. the boiling point and freezing point of the compound
D. the molar mass of the compound.
E. none of these
Feedback: Great! Empirical Formula discussed in Chapter 6.2.
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