Dothkuefan Toys

Chapter $1$ Skill Building Exercises

Measurement, Significant Figures, Rounding, Precision and Accuracy

How many significant figures in each of the following measurements?

$3\mathrm{.}121m$

$0\mathrm{.}051L,2$

$0\mathrm{.}0150L$

$3$

$1\mathrm{.}4{10}^{-4}g2$

$120ft$

$200.$ K

$2.$ Round the following numbers to $3$ significant figures.

$2\mathrm{.}35500,2\mathrm{.}36$

$9\mathrm{.}3859\mathrm{.}39$

$0\mathrm{.}005454\mathrm{.}00545.$

Solve the following and express the answer in the correct number of significant figures.

a$.$ The average mass of $3$ objects whose individual masses are $10\mathrm{.}3g,9\mathrm{.}334g,9\mathrm{.}25g.10\mathrm{.}3q+9\mathrm{.}334+9\mathrm{.}253=28\mathrm{.}884a$ or $28\mathrm{.}9$

b$.$ The volume of a metal block whose dimensions are $2\mathrm{.}44cm$ by $4\mathrm{.}2cm$ by $3\mathrm{.}571cm.$

$2\mathrm{.}44*4\mathrm{.}2*3\mathrm{.}5\%=36\mathrm{.}60$

c$.$ Carry out the following operations and express your answer in the correct number of significant figures.

$\frac{12\mathrm{.}8+12\mathrm{.}71}{0\mathrm{.}560}=V_{5\mathrm{.}55}$

$\frac{155.}{43\mathrm{.}25-7\mathrm{.}1}=4\mathrm{.}288$

Four groups of students where charged with measuring the mass of $10\mathrm{.}0mL$ of a solution of sugar water and from there to calculate the density. The actual mass of the $10\mathrm{.}0mL$ was $12\mathrm{.}348g.$ Given the data below, decide the precision and accuracy of each group. Use the best set of data to calculate the density.

Group A

$12\mathrm{.}348g$

$12\mathrm{.}441g$

$12\mathrm{.}367g$

$12\mathrm{.}392g$

Group B

$12\mathrm{.}412g$

$12\mathrm{.}420g$

$12\mathrm{.}418g$

$12\mathrm{.}415g$

Group C

$12\mathrm{.}321g$

$12\mathrm{.}366g$

$12\mathrm{.}389g$

$12\mathrm{.}314g$

Accurate?

Precise?

Density $=$