# 1.07 Accuracy and Precision

•Below is the table that you will complete for the virtual lab. Either type your results into this table or print the table from the virtual lab (it must be submitted to receive full credit for this assignment.) Part I: Density of Unknown Liquid

Trial 1Trial 2Trial 3Mass of Empty 10 mL graduated cylinder (grams) 2625.6 26 Volume of liquid (milliliters) 8.68.7 8.5Mass of graduated cylinder and liquid (grams) 36.536.5 36.7 Part II: Density of Irregular-Shaped SolidMass of solid(grams) 38.38441.43541.951Volume of water (milliliters) 5150 52Volume of water and solid (milliliters) 57 55 58Part III: Density of Regular-Shaped SolidMass of solid (grams)28.126.126.2Length of solid (centimeters)5.2554.5Width of solid (centimeters)343.5Height of solid (centimeters)2.532CalculationsShow all of your work for each of the following calculations and be careful to follow significant figure rules in each calculation. Part I: Density of Unknown Liquid1.Calculate the mass of the liquid for each trial. (Subtract the mass of the empty graduated cylinder from the mass of the graduated cylinder with liquid.) Trial 1- 10.536.5-26= 10.5Trial 2- 10.936.5-25.6= 10.9Trial 3- 10.736.7-26= 10.72.Calculate the density of the unknown liquid for each trial. (Divide the mass of the liquid calculated above by the volume of the liquid.) Trial 1: 1.2210.5÷8.6= 1.22Trial 2: 1.2610.9÷8.7= 1.26Trial 3: 1.2610.7÷8.5= 1.26Part II: Density of Irregular-Shaped Solid3.Calculate the volume of the irregular-shaped solid for each trial. (Subtract the volume of the water from the total volume of the water and solid.) Trial 1: 657-51= 6Trial 2: 555-50= 5Trial 3: 658-52= 64.Calculate the density of the irregular-shaped solid for each trial. (Divide the mass of the solid by the volume of the solid calculated above.) Trial 1: 6.438.384÷6= 6.4Trial 2: 8.2941.435÷5= 8.29Trial 3: 6.99241.951÷6= 6.992

Part III: Density of Regular-Shaped Solid5.Calculate the volume of the regular shaped solid for each trial. (Multiply the length × width × height for each trial to get the volume in the unit cm3.) Trial 1: 39.38 cm35.25*3*2.5Trial 2: 60 cm35*4*3Trial 3: 31.5 cm34.5*3.5*26.Calculate the density of the regular-shaped solid for each trial. (Divide the mass of the solid by the volume calculated above.) Trial 1: 0.7228.1÷39.39Trial 2: 0.4426.1÷60Trial 3: 0.8426.2÷31.5Questions and Conclusions:1.How would you determine the proper number of significant figures of a liquid using a graduated cylinder? (See practice interactive in “Activity” tab of lesson.) One estimates one decimal place past the smallest division on the cylinder. If the smallest division is to the ones place, then estimate the tenths place. Smallest is in tenths, then estimate to the hundredths place.

2.Can just one measurement be considered precise? Can just one measurement be considered accurate? Explain your answers completely. Just one answer could not be considered precise because the definition of precision clearly states that precision is the agreement among a set of measurements made of the same quantity in the same way. This means that in order for a recording to be precise there must be several measurements. Nonetheless, one measurement can be considered accurate because accuracy refers to the closeness of a measurement to the true or accepted value. As long as that one measurement is close to the measurement of the true value it is accurate.