Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

1. Matter and Measurements

Significant Figures: In Calculations

GOB Chemistry

1. Matter and Measurements

Significant Figures: In Calculations

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Multiple Choice

What answer should be reported, with the correct number of significant figures, for the following calculation?
[(42.00 − 40.914) ⋅ (25.739 − 25.729)] / [(11.50⋅1.001) + (0.00710 ⋅ 700.)]

7.0 x 10^-4

6.67 x 10^-4

6.70 x 10^-4

6.7 x 10^-4

6.75 x 10^-4

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Verified step by step guidance

Identify the number of significant figures in each measurement involved in the calculation. For subtraction and addition, the result should have the same number of decimal places as the measurement with the fewest decimal places. For multiplication and division, the result should have the same number of significant figures as the measurement with the fewest significant figures.

Perform the subtraction in the numerator: (42.00 - 40.914). Note that 42.00 has 2 decimal places, and 40.914 has 3 decimal places. The result should be rounded to 2 decimal places.

Perform the subtraction in the numerator: (25.739 - 25.729). Both numbers have 3 decimal places, so the result should also have 3 decimal places.

Perform the multiplication in the denominator: (11.50 * 1.001). 11.50 has 4 significant figures, and 1.001 has 4 significant figures, so the result should have 4 significant figures.

Perform the multiplication in the denominator: (0.00710 * 700.). 0.00710 has 3 significant figures, and 700. has 3 significant figures, so the result should have 3 significant figures. Then, add the results from the two multiplications in the denominator, ensuring the final result has the correct number of significant figures based on the rules for addition.