Discussion worksheet 1

• Key points to discuss:

  • Main themes introduced in the text

  • Reactions and insights from group members

  • Questions for further exploration

• Follow-up actions:

  • Prepare summary of discussions

  • Schedule next meeting to go over findings.

Significant figures (SIGFIGS)

Significant figures in chemistry:

• Significant figures (also known as sig figs) are the digits in a number that contribute to its precision. They include all non-zero digits, any zeros between non-zero digits, and trailing zeros in a number containing a decimal point.

• Rules for determining significant figures:

  1. All non-zero digits are significant. For example, $123.45$ has five significant figures.

  2. Zeros between non-zero digits are significant. For example, $1002.05$ has six significant figures.

  3. Leading zeros are not significant. For example, $0.002$ has one significant figure.

  4. Trailing zeros in a number containing a decimal point are significant. For example, $1.200$ has four significant figures.

  5. Trailing zeros in a number not containing a decimal point are not significant. For example, $100$ may have one, two, or three significant figures. Use scientific notation to clarify (e.g., $1.0 x 10^2$ has two significant figures).

• Rules for significant figures in calculations:

  1. When adding or subtracting, the result should have the same number of decimal places as the least precise measurement. For example, $1.23 + 0.1 = 1.3$ (one decimal place).

  2. When multiplying or dividing, the result should have the same number of significant figures as the measurement with the fewest significant figures. For example, $1.23 x 2 = 2$ (one significant figure).

• Sig figs are important in chemistry because they are used to determine the accuracy of a measurement.

Worksheet Problem answers ✅ or ❌

Significant figures

1-6) ✅

3, 2 ,4 ,1, 7, 2

7) significant figures are important because they allow us to be as accurate as possible when determining our measurments (accuracy of measurment) ✅

8) The second on is more accurate than the first because the first measurment only contains 2 significant figures. So it could be that 27 centimeters is actually 27.01 or something to that effect. The second measurment has 4 significant figures so we know for a fact that this measurment is closer to 27 than the first one. ✅

9) A .578 technically .579 ✅ B)1.0 ✅

10) 9×10^-3. 9.0×10^-3 ✅

11) 2.3×10^1. 2.30 ×10^1 ✅

12) .02796 ❌ (3×10^-5) round because of 1 sigfig

13) 829.15 °C = K - 273.15. ✅ (dont forget to round sigfigs)

Week 1 Worksheet review

14) a) 150.48 ❌ 174 B)

15)