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

Scientific Notation

GOB Chemistry

1. Matter and Measurements

Scientific Notation

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1:35 minutes

Problem 15d

Textbook Question

Write each of the following in scientific notation with two significant figures:
d. 0.000 25 cm

Verified step by step guidance

Identify the significant figures in the given number. In this case, the number is 0.00025 cm, and the two significant figures are '2' and '5'.

Rewrite the number in standard scientific notation format: \( a \times 10^n \), where \( a \) is a number between 1 and 10, and \( n \) is an integer.

To express 0.00025 in scientific notation, move the decimal point to the right until the number becomes a value between 1 and 10. Count how many places the decimal point is moved. Here, the decimal point is moved 4 places to the right.

Since the decimal point was moved to the right, the exponent \( n \) will be negative. The value of \( n \) is \(-4\).

Combine the significant figures and the exponent to write the number in scientific notation: \( 2.5 \times 10^{-4} \) cm.

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Key Concepts

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

Scientific Notation

Scientific notation is a method of expressing numbers that are too large or too small in a compact form. It is written as the product of a number between 1 and 10 and a power of ten. For example, 0.00025 can be expressed as 2.5 x 10^-4, where 2.5 is the significant figure and -4 indicates the decimal place shift.

Significant Figures

Significant figures are the digits in a number that contribute to its precision. This includes all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion. In the case of 0.00025, the significant figures are '2' and '5', which means the number should be expressed in scientific notation with these two digits.

Decimal Place Shift

Decimal place shift refers to the movement of the decimal point in a number to convert it into scientific notation. This shift determines the exponent of ten in the notation. For instance, moving the decimal point in 0.00025 four places to the right results in the exponent -4, indicating that the original number is a small fraction.