Chemistry Midterm Study Guide

Identify: How well results compare with the known value accepted

Identify: The degree of exactness of a measurement, how close the results are to each other

Example of Accuracy and Precision:

3 students measured the mass of a 50 kg ball 3 times each.

Student 1: 47.2 kg 47.3 kg 49.2 kg

Student 2: 49.2 kg 49.4 kg 49.3 kg

Student 3: 50.1 kg 49.9 kg 50.4 kg

Which set of results are the most accurate?

Example of Accuracy and Precision:

3 students measured the mass of a 50 kg ball 3 times each.

Student 1: 47.2 kg 47.3 kg 49.2 kg

Student 2: 49.2 kg 49.4 kg 49.3 kg

Student 3: 50.1 kg 49.9 kg 50.4 kg

Which set of results are the most precise?

How many significant figures are on the following?

9043.20

How many significant figures are on the following?

9190

How many significant figures are on the following?

5,000,000

How many significant figures are on the following?

0.00430

Identify: Measure of how much matter takes up volume

What is the formula for density?

• density=mass/volume

• density=volume/mass

• density=matter/mass

• density=weight/mass