Help w/ Significant Figures - Sig Figs?

Question

Hello:

Once again, I need help with sig figs:

Complete the following problems in scientific notation. Round off to the correct number of significant figures


1. (5.31 x 10^ -2 cm) x (2.46 x 10^5 cm) =

2. (3.78 x 10^3 m) x (7.21 x 10^2 m) =

3. (8.12 x 10^ -3 m) x (1.4 x 10^ -5 m) =

4. (9.33 x 10^4 mm) / (3.0 x 10^2 mm) =

5. (4.42 x 10^ -3 kg) / (2.0 x 10^2 kg) =

Thanks alot-

Answer 1

Do your homework yourself.

Answer 2

the rule in mutiplication and division is that the sig. figure of the answer is the same as the least sig. figure of the factors

like 1.0 * 1.00 = 1.0 or 1.000 / 1.00 = 1.00
or 1.00000 * 1. 00 * 1 = 1

1. (5.31 x 10^ -2 cm) x (2.46 x 10^5 cm) = 13.0626 * 10^3 cm because 5.31 and 2.46 has both two sig figures, the answer should also have 3 sig. figures so the asnwer = 13.1 * 10^3 = 1.31 * 10^4 cm

5. (4.42 x 10^ -3 kg) / (2.0 x 10^2 kg) = 8.82 * 10^-1 because 2.0 has two sig figures and the least sig figures (4.42 has 3 sig. figures), the answer must laso have 2 sig figures, so the answer = 8.8*10^-1 kg or 0.88 kg

the rest are the same as two above, u can do it

Answer 3

for significant figures, do the round up or round down of a No. eg.,express 399 in 1 sig. fig you get 400, 3 being the most significant No. in 399 and the 9 after 3 is more than 5. Therefore you round up to get 400 ( 1 s.f.) Express 3.04264 in 3 s. figs, the ans. is 3.04. Thus 400 has 1 s. f. (ans)

Answer 4

1.)
(5.31 * 10^-2)(2.46 * 10^5)
(5.31 * 2.46)(10^(-2 + 5))
13.0626 * 10^3
(1.30626 * 10^1) * 10^3
1.30626 * 10^(1 + 3)
1.30626 * 10^4

ANS : 1.31 * 10^4

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2.)
(3.78 * 10^3)(7.21 * 10^2)
(3.78 * 7.21)(10^(3 + 2))
27.2538 * 10^5
(2.72538 * 10^1) * 10^5
2.72538 * 10^(1 + 5)
2.72538 * 10^6

ANS : 2.73 * 10^6

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3.)
(8.12 * 10^-3)(1.4 * 10^-5)
(8.12 * 1.4)(10^(-3 + (-5)))
11.368 * 10^(-8)
(1.1368 * 10^1) * 10^(-8)
1.1368 * 10^(1 - 8)
1.1368 * 10^(-7)

ANS : 1.1 * 10^(-7)

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4.)
(9.33 * 10^4)/(3.0 * 10^2)
(9.33/3)(10^(4 - 2))
3.11 * 10^2

ANS : 3.1 * 10^2

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5.)
(4.42 * 10^-3)/(2.0 * 10^2)
(4.42/2)(10^(-3 - 2))
2.21 * 10^(-3 + (-2))
2.21 * 10^(-5)

ANS : 2.2 * 10^(-5)

Answer 5

i hate sig figs! just remember those rules. in this case, you'd solve it out on a calculator and then round off so that the final answer has the same number of sig figs as the measurement with the smallest number of sig figs (in total, not just after the decimal) you can do it!