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 (Simplified)

GOB Chemistry

1. Matter and Measurements

Significant Figures (Simplified)

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1:43 minutes

Problem 17a

Textbook Question

Identify the numbers in each of the following statements as measured or exact:
a. A patient has a mass of 67.5 kg.

Verified step by step guidance

Step 1: Understand the difference between measured and exact numbers. Measured numbers are obtained using a measuring tool and have a degree of uncertainty, while exact numbers are counted or defined and have no uncertainty.

Step 2: Analyze the given statement: 'A patient has a mass of 67.5 kg.' The number 67.5 is associated with the mass of the patient, which is typically determined using a scale or measuring device.

Step 3: Recognize that the use of a measuring device introduces uncertainty, even if the number is reported to a specific decimal place. This indicates that the number is a measured value.

Step 4: Confirm that mass is a physical quantity that cannot be counted or defined exactly, further supporting that 67.5 kg is a measured number.

Step 5: Conclude that the number 67.5 kg in the statement is a measured number because it was obtained using a measuring tool and has a degree of uncertainty.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Measured Numbers

Measured numbers are values obtained through measurement and are subject to uncertainty. They include a degree of error based on the precision of the measuring instrument used. For example, the mass of a patient measured as 67.5 kg reflects the limitations of the scale, indicating that the true mass could vary slightly.

Exact Numbers

Exact numbers are values that are counted or defined and have no uncertainty associated with them. They are considered to be infinitely precise. Examples include the number of patients in a study or defined quantities like 100 centimeters in a meter, which do not vary regardless of measurement conditions.

Significant Figures

Significant figures are the digits in a number that contribute to its precision, including all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion. Understanding significant figures is crucial for interpreting measured numbers, as they indicate the reliability of the measurement and help in maintaining precision in calculations.