Other Decimals

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Questions 1 - 10
1

A chemistry students needs to dilute some acid. How much water should be added to 2 L of 80% acid solution to yield 50% acid solution?

0.8 L

1.0 L

1.2 L

1.5 L

2.0 L

Explanation

Pure water would be 0% solution and pure solution would be 100%

V1P1 + V2P2 = VfPf

Let x = amount of water to add

x(0) + 2(0.80) = (x + 2)(0.50) which when solved gives x = 1.2 L

2

A chemistry students needs to dilute some acid. How much water should be added to 2 L of 80% acid solution to yield 50% acid solution?

0.8 L

1.0 L

1.2 L

1.5 L

2.0 L

Explanation

Pure water would be 0% solution and pure solution would be 100%

V1P1 + V2P2 = VfPf

Let x = amount of water to add

x(0) + 2(0.80) = (x + 2)(0.50) which when solved gives x = 1.2 L

3

Divide:

Explanation

Rewrite so that both are in fraction form.

Convert the division sign to multiplication, and take the reciprocal of the 2nd term.

4

Divide:

Explanation

Rewrite so that both are in fraction form.

Convert the division sign to multiplication, and take the reciprocal of the 2nd term.

5

Write the following number in scientific notation:

\dpi{100} \small 175,000,000

\dpi{100} \small 1.75 \times 10^{8}

\dpi{100} \small 17.5 \times 10^{7}

\dpi{100} \small 175 \times 10^{6}

\dpi{100} \small .175 \times 10^{5}

\dpi{100} \small 1.75 \times 10^{7}

Explanation

Slide the decimal point to the left as many places as you need to make a number between 1 and 10. Multiply that number by 10 to the power of however many decimal places you moved the decimal.

6

A runner runs 10.2 miles east, then 2.3 miles west, then 1.4 miles east.

How many miles did the runner travel from where he started? (How far east did the runner go)?

9.3 miles

10.2 miles

6.5 miles

13.9 miles

19.3 miles

Explanation

When the runner is travelling east, it's in the positive direction. West is the negative direction. So we can compute it by doing the operation 10.2 + (–2.3) + 1.4 = 9.3

7

Write the following number in scientific notation:

\dpi{100} \small 175,000,000

\dpi{100} \small 1.75 \times 10^{8}

\dpi{100} \small 17.5 \times 10^{7}

\dpi{100} \small 175 \times 10^{6}

\dpi{100} \small .175 \times 10^{5}

\dpi{100} \small 1.75 \times 10^{7}

Explanation

Slide the decimal point to the left as many places as you need to make a number between 1 and 10. Multiply that number by 10 to the power of however many decimal places you moved the decimal.

8

A runner runs 10.2 miles east, then 2.3 miles west, then 1.4 miles east.

How many miles did the runner travel from where he started? (How far east did the runner go)?

9.3 miles

10.2 miles

6.5 miles

13.9 miles

19.3 miles

Explanation

When the runner is travelling east, it's in the positive direction. West is the negative direction. So we can compute it by doing the operation 10.2 + (–2.3) + 1.4 = 9.3

9

Evaluate

Explanation

First,

Then,

10

If 3.0147 * 10_n_ = 3,014,700,000, then n =

–8

–4

2

8

9

Explanation

To determine this answer, move the decimal point in 3.0147 until you get 3,014,700,000 (9 places). There are 9 decimal places after the decimal point.

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