A pre-1955 quarter is found to be 85% by mass pure silver: a. What is the mass of silver in grams based on your quarter mass? b. Silver is currently valued at $0.49 per gram, what is the value of the silver in the quarter? 2. A 1-lb jar of peanut butter is found to have a volume of 436.6 cm3. What is the density of peanut butter? Would you expect peanut butter to float or sink in water?

1.

2.

Given:

1) Mass of pre-1955 quarter is 5.670g, 85% of silver by mass.

Silver is currently valued at $0.49 per gram.

2) A 1-lb jar of peanut butter is found to have a volume of

To find:

Mass of silver in pre-1955 quarter

The value of silver in quarter

Density of the peanut butter

Whether peanut buter will float or sink in water.

Solution:

1) Mass of pre-1955 quarter = 5.670g

The percentage of the silver in the quarter =85%

Mass of silver in pre-1955 quarter=

The mass of silver in quater is 4.1895 grams,

The current value of the silver =  $0.49 per gram g

The value of silver in quarter :

The value of the silver in the quarter is $2.36.

2)

The mass of peanut butter in jar = m = 1 lb = 453.592 g

The volume of peanut butter in the jar = v =

The density of the peanut jar = d

The density of peanut butter is  

The density of the water = D =

d > D

The density of peanut butter is greater than density of water which indicates that peanut butter will sink in water.

Learn more about perentage mass and density here:

link

link

Explanation:

1a. 85% of 5.670 g is ...

  0.85 × 5.670 g = 4.8195 g . . . . mass of silver

1b. The value of that will be ...

  (4.8195 g)($0.49/g) ≈ $2.36 . . . . value of silver in a pre-1955 quarter

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2. 1 pound is 453.59237 g (exactly), so the density of the peanut butter is ...

  density = mass/volume = (453.59237 g)/(436.6 cm^3)

  density ≈ 1.0389 g/cm^3

We expect this peanut butter to sink in water, as its density is more than the 1.00 g/cm^3 density of water.