General Chemistry Chapter 1: Matter, Measurement, and Problem Solving – Guided Study Notes

Q1. Classify the following as a pure substance, mixture, element, compound, homogeneous mixture, or heterogeneous mixture.

Background

Topic: Classification of Matter

This question tests your understanding of how matter is categorized based on its composition and uniformity.

Key Terms:

• Pure substance: Matter with a fixed composition (element or compound).

• Element: Substance made of one type of atom.

• Compound: Substance made of two or more elements chemically bonded.

• Mixture: Physical blend of two or more substances.

• Homogeneous mixture: Uniform composition throughout (solution).

• Heterogeneous mixture: Non-uniform composition.

Step-by-Step Guidance

1. Read each example (e.g., dirt, I.V. solution, nitrogen) and consider its composition.

2. Ask: Is it made of only one kind of atom (element), more than one but chemically bonded (compound), or a physical blend (mixture)?

3. If a mixture, decide if it looks the same throughout (homogeneous) or has visible differences (heterogeneous).

4. Use definitions above to classify each item.

Try solving on your own before revealing the answer!

Q2. Classify each as a physical change, chemical change, physical property, or chemical property.

Background

Topic: Properties and Changes of Matter

This question tests your ability to distinguish between physical and chemical properties and changes.

Key Terms:

• Physical property: Can be observed/measured without changing substance identity (e.g., melting point).

• Chemical property: Describes ability to undergo chemical change (e.g., flammability).

• Physical change: Change in state or appearance, not composition (e.g., freezing).

• Chemical change: Alters composition (e.g., rusting).

Step-by-Step Guidance

1. Read each statement (e.g., "Gold is resistant to corrosion").

2. Ask: Is this describing a property or a change?

3. If a property, does it involve a chemical reaction or just observation?

4. If a change, does the substance's identity change?

Try solving on your own before revealing the answer!

Q3. What is the symbol of the prefix used for the numeric value?

Background

Topic: Metric Prefixes

This question tests your knowledge of metric system prefixes and their symbols.

Key Terms:

• Prefix: Symbol that represents a power of ten (e.g., kilo-, centi-, milli-).

Step-by-Step Guidance

1. Identify the numeric value given (e.g., 10^3, 10^-6).

2. Recall the corresponding metric prefix and its symbol (e.g., kilo = k).

3. Write the symbol next to the value.

Try solving on your own before revealing the answer!

Q4. Temperature Conversion Equations

Background

Topic: Temperature Scales and Conversions

This section provides formulas for converting between Fahrenheit, Celsius, and Kelvin.

Key Formulas:

• $^\circ F = (1.8 \times ^\circ C) + 32$

• $^\circ C = \frac{(^\circ F - 32)}{1.8}$

• $K = ^\circ C + 273.15$

Try solving on your own before revealing the answer!

Q5. How cold is absolute zero in Fahrenheit?

Background

Topic: Absolute Zero and Temperature Conversion

This question tests your ability to convert the lowest possible temperature (absolute zero) from Kelvin to Fahrenheit.

Key Terms and Formulas:

• Absolute zero: 0 K

• Use $^\circ C = K - 273.15$ and $^\circ F = (1.8 \times ^\circ C) + 32$

Step-by-Step Guidance

1. Start with absolute zero in Kelvin: $K = 0$

2. Convert to Celsius: $^\circ C = 0 - 273.15$

3. Convert Celsius to Fahrenheit using the formula above.

Try solving on your own before revealing the answer!

Q6. What is the equivalent temperature for 59°F on the Celsius scale?

Background

Topic: Temperature Conversion

This question tests your ability to convert Fahrenheit to Celsius.

Key Formula:

• $^\circ C = \frac{(^\circ F - 32)}{1.8}$

Step-by-Step Guidance

1. Write down the given temperature in Fahrenheit: $^\circ F = 59$

2. Plug the value into the conversion formula above.

3. Calculate the result, keeping track of significant figures.

Try solving on your own before revealing the answer!

Q7. Calculate the mass in grams of an iron block that is 2.50 cm × 3.00 cm × 2.85 cm. The density of iron is 7.874 g/cm³.

Background

Topic: Density Calculations

This question tests your ability to use density to find mass from volume and vice versa.

Key Formula:

• $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$

• Rearranged: $\text{Mass} = \text{Density} \times \text{Volume}$

Step-by-Step Guidance

1. Calculate the volume of the block: $V = 2.50 \times 3.00 \times 2.85$ (in cm³).

2. Multiply the volume by the density to find the mass.

3. Check significant figures in your calculation.

Try solving on your own before revealing the answer!

Q8. How much does 3785 mL of antifreeze weigh in grams? The density of antifreeze is 1.1132 g/cm³.

Background

Topic: Density and Mass Calculations

This question tests your ability to use density to convert volume to mass.

Key Formula:

• $\text{Mass} = \text{Density} \times \text{Volume}$

Step-by-Step Guidance

1. Convert mL to cm³ (1 mL = 1 cm³).

2. Multiply the volume by the density to get the mass in grams.

3. Check significant figures.

Try solving on your own before revealing the answer!

Q9. Graduated Cylinder and Thermometer: Increment and Measurement

Background

Topic: Laboratory Measurement

This question tests your ability to read laboratory instruments and understand increments and estimated values.

Key Terms:

• Increment: The value between two marks on a measuring device.

• Measurement: The value you read, including one estimated digit.

Step-by-Step Guidance

1. Look at the images of the graduated cylinder and thermometer.

2. Identify the value between marks (increment).

3. Estimate the measurement, including one digit beyond the smallest increment.

Try solving on your own before revealing the answer!

Q10. What is the estimated place value for the given incremental marks?

Background

Topic: Significant Figures in Measurement

This question tests your understanding of how to estimate the last digit in a measurement based on the instrument's increments.

Key Terms:

• Estimated place value: The digit you estimate beyond the smallest increment.

Step-by-Step Guidance

1. For each incremental mark (e.g., 1°C, 0.1°C, 25 mL, 0.2 mL), determine the next smallest place value.

2. Write the estimated place value for each.

Try solving on your own before revealing the answer!

Q11. In these measurements, which digits are known with certainty and which is estimated?

Background

Topic: Significant Figures

This question tests your ability to distinguish between certain and estimated digits in a measurement.

Key Terms:

• Certain digits: Digits determined directly from the instrument's marks.

• Estimated digit: The last digit, which is uncertain and estimated.

Step-by-Step Guidance

1. Look at the measurement and identify all digits except the last as certain.

2. The last digit is always estimated.

Try solving on your own before revealing the answer!

Q12. What kind of zero? Are they significant?

Background

Topic: Significant Figures and Zeros

This question tests your understanding of which zeros are significant in a number.

Key Terms:

• Leading zeros: Zeros before nonzero digits (not significant).

• Captive zeros: Zeros between nonzero digits (significant).

• Trailing zeros: Zeros after nonzero digits (significant if decimal is present).

Step-by-Step Guidance

1. For each number, identify the type of zero(s) present.

2. Decide if the zeros are significant based on their position and the presence of a decimal point.

Try solving on your own before revealing the answer!

Q13. How many significant figures are in each measurement?

Background

Topic: Counting Significant Figures

This question tests your ability to count the number of significant digits in a measurement.

Key Terms:

• Significant figures: All nonzero digits, captive zeros, and trailing zeros (if decimal is present).

Step-by-Step Guidance

1. For each measurement, apply the rules for significant figures.

2. Count the number of significant digits and record your answer.

Try solving on your own before revealing the answer!

Q14. Fill in the following chart: Decimal form → Scientific Notation, Scientific Notation → Decimal form

Background

Topic: Scientific Notation

This question tests your ability to convert between decimal and scientific notation.

Key Terms:

• Scientific notation: Expresses numbers as a product of a coefficient and a power of ten.

Step-by-Step Guidance

1. For decimal to scientific notation, move the decimal point to create a number between 1 and 10, then count the places moved for the exponent.

2. For scientific notation to decimal, move the decimal point according to the exponent.

Try solving on your own before revealing the answer!

Q15. Solve the equations below, and report your final answer with the correct number of significant figures.

Background

Topic: Calculations with Significant Figures

This question tests your ability to perform calculations and report answers with the correct number of significant figures.

Key Terms:

• Multiplication/division: Answer has same number of sig figs as the least precise value.

• Addition/subtraction: Answer has same decimal places as the least precise value.

Step-by-Step Guidance

1. Perform the calculation as written.

2. Apply the rules for significant figures to round your answer appropriately.

Try solving on your own before revealing the answer!

Q16. Identify which piece of glassware is the most accurate and precise for measuring 50 mL of a liquid.

Background

Topic: Accuracy and Precision in Measurement

This question tests your ability to interpret data and determine which instrument is most accurate and precise.

Key Terms:

• Accuracy: How close measurements are to the true value.

• Precision: How close measurements are to each other.

Step-by-Step Guidance

1. Examine the trial data for each glassware.

2. Determine which set is closest to 50 mL (accuracy) and which has the least variation (precision).

Try solving on your own before revealing the answer!

Q17. Write conversion factors for the metric prefixes in CH3.

Background

Topic: Metric System and Conversion Factors

This question tests your ability to write conversion factors for metric prefixes (e.g., kilo, centi, milli).

Key Terms:

• Conversion factor: Ratio used to convert between units.

Step-by-Step Guidance

1. Recall the value of each prefix (e.g., 1 km = 1000 m).

2. Write the conversion factor as a ratio.

Try solving on your own before revealing the answer!

Q18. What is the equivalent quantity for 1.6 ft in inches? In yards?

Background

Topic: Unit Conversion

This question tests your ability to convert between feet, inches, and yards.

Key Conversion Factors:

• 1 ft = 12 in

• 1 yd = 3 ft

Step-by-Step Guidance

1. Multiply feet by 12 to get inches.

2. Divide feet by 3 to get yards.

Try solving on your own before revealing the answer!

Q19. How many micrograms (μg or ug) are in 1.46 kg?

Background

Topic: Metric Conversions

This question tests your ability to convert kilograms to micrograms.

Key Conversion Factors:

• 1 kg = 10^6 mg

• 1 mg = 10^3 μg

Step-by-Step Guidance

1. Convert kg to g, then g to mg, then mg to μg.

2. Multiply through each step.

Try solving on your own before revealing the answer!

Q20. How many kilograms is 39.3 oz?

Background

Topic: Unit Conversion (Imperial to Metric)

This question tests your ability to convert ounces to kilograms.

Key Conversion Factors:

• 1 oz = 28.3495 g

• 1 kg = 1000 g

Step-by-Step Guidance

1. Multiply ounces by 28.3495 to get grams.

2. Divide grams by 1000 to get kilograms.

Try solving on your own before revealing the answer!

Q21. What will be the mass of a green substance that occupies 25.0 cm³ and has a density of 1.43 g/cm³?

Background

Topic: Density Calculations

This question tests your ability to use density to find mass.

Key Formula:

• $\text{Mass} = \text{Density} \times \text{Volume}$

Step-by-Step Guidance

1. Multiply the given volume by the density.

2. Check significant figures.

Try solving on your own before revealing the answer!

Q22. How many grams are in 225 mL of oil? The density of the oil is 0.703 g/mL.

Background

Topic: Density and Mass Calculations

This question tests your ability to use density to convert volume to mass.

Key Formula:

• $\text{Mass} = \text{Density} \times \text{Volume}$

Step-by-Step Guidance

1. Multiply the volume by the density to get the mass in grams.

2. Check significant figures.

Try solving on your own before revealing the answer!

Q23. Calculate the mass in grams of an iron block that is 2.50 cm × 3.00 cm × 2.85 cm. The density of iron is 7.874 g/cm³.

Background

Topic: Density Calculations

This question tests your ability to use density to find mass from volume.

Key Formula:

• $\text{Mass} = \text{Density} \times \text{Volume}$

Step-by-Step Guidance

1. Calculate the volume: $V = 2.50 \times 3.00 \times 2.85$

2. Multiply the volume by the density.

3. Check significant figures.

Try solving on your own before revealing the answer!

Q24. What is the density in grams per cubic centimeter of antifreeze if 1.00 gallon weighs 4214 grams?

Background

Topic: Density Calculations and Unit Conversion

This question tests your ability to convert volume units and calculate density.

Key Conversion Factors:

• 1 gallon = 3.785 L = 3785 mL = 3785 cm³

• $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$

Step-by-Step Guidance

1. Convert gallons to cm³.

2. Divide the mass by the volume to get density.

3. Check significant figures.

Try solving on your own before revealing the answer!

Q25. What is the volume of a room in cubic feet that measures 5.83 m × 4.25 m × 3.05 m?

Background

Topic: Volume Calculations and Unit Conversion

This question tests your ability to calculate volume and convert between metric and imperial units.

Key Conversion Factor:

• 1 m³ = 35.3147 ft³

Step-by-Step Guidance

1. Calculate the volume in m³: $V = 5.83 \times 4.25 \times 3.05$

2. Convert m³ to ft³ using the conversion factor.

3. Check significant figures.

Try solving on your own before revealing the answer!