How much KCl in grams is in 0.337 L of a 5.80 % mass percent KCl solution? (Assume that the density of the solution is 1.05 g/mL.)
GIVEN: 5.80% KCl by mass
0.337 L solution
FIND: g KCl
RELATIONSHIPS USED
\frac{5.80 g\,\mathrm{KCI}}{100\,\mathrm{g}\,\mathrm{solution}} (given mass percent, written as a fraction)
\frac{105 g}{mL} (given density)
1 mL = 10^{-3} L (Table 2.2)
0.337 \cancel{\mathrm{L\; solution}} \times \frac{1 \cancel{mL}}{10^{-3} \cancel{L}} \times \frac{1.05 \cancel{g}}{ \cancel{mL}} \times \frac{5.80 g KCl}{ 100 \cancel{\mathrm{g \; solution}}} \\ =20.5 g KClThe units (g KCl) are correct. The magnitude of the answer makes sense because 0.337 L is a bit more than 300 g of solution. Each 100 g of solution contains about 6 g KCl, Therefore the answer should be a bit more than 18 g.
TABLE 2.2 SI Prefix Multipliers | |||||
Prefix | Symbol | Multiplier | |||
tera- | T | 1,000,000,000,000 | (10^{12}) | ||
giga- | G | 1,000,000,000 | (10^9) | ||
mega- | M | 1,000,000 | (10^6) | ||
kilo- | k | 1,000 | (10^3) | ||
deci- | d | 0.1 | (10^{-1}) | ||
centi- | c | 0.01 | (10^{-2}) | ||
milli- | m | 0.001 | (10^{-3}) | ||
micro- | \mu | 0.000001 | (10^{-6}) | ||
nano- | n | 0.000000001 | (10^{-9}) | ||
pico- | p | 0.000000000001 | (10^{-12}) | ||
femto- | f | 0.000000000000001 | (10^{-15}) |