Pre$-$Lab Study Questions $1.$ What are the rules for rounding off numbers? $2.$ How do you determine how many significant figures to keep in an answer obtained by multiplying or dividing? $3.$ How is the number of digits determined for an answer obtained by adding or subtracting? $4.$ Is a body temperature of $39\mathrm{.}4\backslash$deg C a normal temperature or does it indicate a fever? $5.$ What is an equality and how is it used to write a conversion factor? A$.$ Rounding off A$\mathrm{.}1$ Rounding A student rounded off the following calculator displays to three significant figures. Indicate if the rounded number is correct. If it is incorrect, round off the display value properly. Calculator Student's Correct $($yes$/$no$)$ Corrected $($if needed$)$ Display Rounded Value $24\mathrm{.}470424\mathrm{.}5143\mathrm{.}632125328005300\mathrm{.}008583450\mathrm{.}00914488\mathrm{.}0017$ Laboratory $2$ Report Sheet $-$ Lab $2$ A$\mathrm{.}2$ Area $11$ Another student's measurements Your measurements Length $=$ Width $=$ Area $=($Show calculations.$)$ Why could two students obtain different values for the calculated areas of the same rectangle? A$\mathrm{.}3$ Volume of a solid by direct measurement Shape of solid Formula for volume of solid Height Length Width Diameter $($if cylinder$)$ Volume of the solid $($Show calculations of volume including the units.$)$ Report Sheet $-$ Lab $2$ B$.$ Significant Figures in Calculations B$\mathrm{.}1$ Perform the following multiplication and division calculations. Give a final answer with the correct number of significant figures: $4\mathrm{.}5$ x $0\mathrm{.}280\mathrm{.}1184$ x $8\mathrm{.}000\mathrm{.}0345(42\mathrm{.}4)(15\mathrm{.}6)1\mathrm{.}265(35\mathrm{.}56/1\mathrm{.}45)(4\mathrm{.}8$X$0\mathrm{.}56)$ B$\mathrm{.}2$ Perform the following addition and subtraction calculations. Give a final answer with the correct number of significant figures. $13\mathrm{.}45$ mL $+0\mathrm{.}4552$ mL $145\mathrm{.}5$ m $+86\mathrm{.}58$ m $+1045$ m $1315+200+1100245\mathrm{.}6258-80\mathrm{.}284\mathrm{.}62$ cm $-0\mathrm{.}885$ cm Questions and Problems Q$\mathrm{.}1$ What is the combined mass in grams of objects that have masses of $0\mathrm{.}2000$ kg$,80\mathrm{.}0$ g$,$ and $524$ mg$?$ Q$\mathrm{.}2$ A beaker has a mass of $225\mathrm{.}088.$ When a liquid is added to the beaker, the combined mass is $238\mathrm{.}254$ g$.$ What is the mass in grams of the liquid? Laboratory $2$ Report Sheet $-$ Lab $2$ C$.$ Conversion Factors for Length c$\mathrm{.}1$ Metric factors Equality: $1$ m mm Conversion factors: m and mm mm m Equality: $1$ cm $=$ mm Conversion factors: cm and mm mm cm C$\mathrm{.}2$ Metric$-$U$.$S$.$ system factors Line length $($measured$)$ cm cm cm $($Experimental ratio$)$ in$.1$ in$.$ How close is your experimental ratio to the standard conversion factor of $2\mathrm{.}54$ cm$/$in$?$ Conversion Factors in Calculations Report Sheet $-$ Lab $2$ C$\mathrm{.}3$ Your metric height Height $($inches$)$ Height in centimeters $($calculated$)$ in x What is your height in meters? $($Show your calculations here.$)$ cm cm $1$ in Questions and Problems $($Show complete setups.$)$ Q$3$ A pencil is $16\mathrm{.}2$ cm long. What is its length in millimeters $($mm$)?$ Q$\mathrm{.}4$ A roll of tape measures $45\mathrm{.}5$ inches. What is the length of the tape in meters? D$.$ Conversion Factors for Volume D$\mathrm{.}1$ Equality: IL $=$ ml Conversion factors: mL and mL ml D$\mathrm{.}2$ Volume $($mL$)$ of $1$ quart of water: Number of milliliters in $1$ quart: mL$/$t $($experimental$)$ ml Equality: $191$ Conversion factors: mL and ml Laboratory $2$ Report Sheet $-$ Lab $2$ Questions and Problems $($Show complete setups.$)$ Q$5$ A patient received $825$ mL of fluid in one day. What is that volume in liters? Q$\mathrm{.}6$ How many liters of plasma are present in $8\mathrm{.}5$ pints? $(1$ qt $=2$ pt$)$ E$.$ Conversion Factors for Mass El Grams and pounds Name of commercial product Mass in grams stated on label Weight in lb or oz given on label Weight in lb $($Convert oz to lb if needed.$)$ Number of grams Number of lb Ib $1$ lb How does your experimental factor compare to the standard value of $454$ g$/$lb$?$ E$\mathrm{.}2$ Pounds and kilograms Mass in kilograms $($from label$)$ Weight in to Ib Number of lb Number of kg kg $1$ kg How does your experimental factor compare to the standard value of $2\mathrm{.}2011/$kg$?$ Questions and Problems Q$7$ An infant has a mass of $3\mathrm{.}40$ kg$.$ What is the weight of the infant in pounds? Conversion Factors in Calculations Report Sheet $-$ Lab $2$ F$.$ F$\mathrm{.}1$ F$\mathrm{.}2$ F$\mathrm{.}3$ F$\mathrm{.}4$ Percent by Mass Mass of the beaker $(0$ if tared$)$ Mass of the sugar $+$ the beaker Mass of the sugar$-$water mixture $+$ beaker Calculations: What is the mass of sugar? What is the mass of the sugar$-$water mixture? What is the mass of the water added? What is the $\%$ sugar $($by mass$)?($Show calculations.$)$ What is the $\%$ water $($by mass$)?($Show calculations.$)$ Questions and Problems $($Show complete setups$)$ Q$\mathrm{.}8$ A sugar$-$water mixture contains $45\mathrm{.}8$ g of sugar and $108\mathrm{.}5$ g of water. What is the percent by mass of sugar and the percent by mass of water in the solution? $23$ Laboratory $2$ G$.$ Converting Temperature G$\mathrm{.}1$ Temperature scale$($s$)$ on the laboratory thermometer Lowest temperature Highest temperature G$\mathrm{.}2\backslash$deg C $($G$\mathrm{.}3)\backslash$deg F K a$.$ Room temperature b$.$ Tap water c$.$ Ice$-$water mixture d$.$ Salt ice$-$water mixture Questions and Problems Q$\mathrm{.}9$ Write an equation for each of the following temperature conversions: a$.\backslash$deg C to $\backslash$deg F b$.\backslash$deg F to $\backslash$deg C c$.\backslash$deg C to K Q$\mathrm{.}10$ A recipe calls for a baking temperature of $205\backslash$deg C$.$ What temperature in $\backslash$deg F should be set on the oven?

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