Question

multiply or divide the following measurements. be sure each answer you enter contains the correct number of significant digits.
706.04 mol ÷ 56.562 l = mol/l
20.94 cm × 13. cm = cm²
806.9 mol ÷ 0.32 l = mol/l

Explanation:

Step1: First calculation ($706.04\space mol\div56.562\space L$)

When dividing, the number of significant figures in the result is determined by the least number of significant figures in the values being divided.
$706.04$ has 5 significant figures, $56.562$ has 5 significant figures.
$$706.04\div56.562=\frac{706.04}{56.562}\approx12.5$$

Step2: Second calculation ($20.94\space cm\times13\space cm$)

When multiplying, $20.94$ has 4 significant figures, $13$ has 2 significant figures.
$$20.94\times13=(20 + 0.94)\times13=20\times13+0.94\times13=260+12.22 = 272.22\approx270$$

Step3: Third calculation ($806.9\space mol\div0.32\space L$)

$806.9$ has 4 significant figures, $0.32$ has 2 significant figures.
$$806.9\div0.32=\frac{806.9}{0.32}\approx2500$$

Answer:

$12.5\space\frac{mol}{L}$; $270\space cm^{2}$; $2500\space\frac{mol}{L}$