Complete each calculation. Express your answer to the correct number of significant digits.
a)4.02mL + 3.76mL +0.95mL
b)(2.7 x 10^2m) x (4.23 x 10^2m)
c)5092kg divided by 23L
d) 2-6.3 + 6-7
e)(6.853 x 10^3L) + (5.40 x 10^3mL)
f)(572.3g + 794.1g) divided (24mL + 52mL)
My answers:
a)8.7mL
b) i am not sure
c) 221.34
d) -5.3
e) im not sure
f) 17.97
thank you so much, yes the site is helpful
To complete each calculation and express the answer to the correct number of significant digits, follow these steps:
a) 4.02mL + 3.76mL + 0.95mL:
- Add the three values: 4.02 + 3.76 + 0.95 = 8.73
- The least number of significant digits in the given values is two (0.95).
- Therefore, the answer should be expressed with two significant digits, which means it should be rounded to 8.7.
- The final answer is 8.7mL.
b) (2.7 x 10^2m) x (4.23 x 10^2m):
- Multiply the two values: (2.7 x 4.23) x (10^2 x 10^2) = 11.421 x 10^4
- The given values have a total of four significant digits, but the multiplication introduces an additional digit. To express the answer in the correct number of significant digits, we need to round it to four significant digits.
- The final answer is 1.142 x 10^5m.
c) 5092kg / 23L:
- Divide the two values: 5092 / 23 = 221.391304348
- The given values have four and two significant digits, respectively. To express the answer using the correct number of significant digits, we need to round it to match the significant figures in the value with the least significant digits.
- The final answer is 221.39.
d) 2-6.3 + 6-7:
- Perform the subtraction: 2 - 6.3 + 6 - 7 = -5.3
- The answer has three significant digits, matching the given values.
- The final answer is -5.3.
e) (6.853 x 10^3L) + (5.40 x 10^3mL):
- Convert the milliliters to liters: 5.40 x 10^3mL = 5.40L
- Add the two values: (6.853 + 5.40) x 10^3 = 12.253 x 10^3
- The given values have four significant digits, but the addition introduces an additional digit. To express the answer using the correct number of significant digits, we need to round it to four significant digits.
- The final answer is 1.225 x 10^4L.
f) (572.3g + 794.1g) / (24mL + 52mL):
- Add the two masses: 572.3 + 794.1 = 1366.4g
- Add the two volumes: 24 + 52 = 76mL
- Now perform the division: 1366.4g / 76mL = 17.9589473684
- The given values have four significant digits, but the division introduces additional digits. To express the answer using the correct number of significant digits, we need to round it to four significant digits.
- The final answer is 17.96.
a. You are allowed to the hundredths place so the answer should be 8.73.
b. 1.1421E5. In mult and division, you are allowed as many places in the answer as you have the smallest number that has been mult or divided. You have 2 s.f. in 2.7E2 and 3 in 4.23E2 so you are allowed 2 in the answer. So you round 1.1421E5 to 1.1E5.
c. 2.213913E2. From the rule above you are allowed 2 s.f. and the answer is rounded to 2.2E2 kg/L.
d. -5.30. You are allowed only units (no tenths) so round to -5
e. 12.253E3. You are allowed to the hundredths so round to 12.25E3 or 1.225E4
r. 17.9789 Adding the first two numbers is ok to the tenths or 4 s.f. The divisor has 2 s.f. So you're allowed 2 in the answer which should be rounded to 18
I think you need to review s.f. Here is a good site.
http://www.chemteam.info/SigFigs/SigFigs.html