Introductory Chemistry Exam Study Guide with Step-by-Step Guidance

Q1. Which of the following is not a state of matter?

Background

Topic: States of Matter

This question tests your understanding of the basic states of matter and their properties.

Key Terms:

• Solid, liquid, gas: The three classical states of matter.

• Plasma: A fourth state, not always covered in intro courses.

Step-by-Step Guidance

1. Recall the three main states of matter commonly discussed in introductory chemistry: solid, liquid, and gas.

2. Consider the properties of each option given in the question and determine which one does not fit the definition of a state of matter.

3. Eliminate any choices that are not physical states (e.g., forms of energy or processes).

Try solving on your own before revealing the answer!

Q2. Which of the following is a chemical compound?

Background

Topic: Elements, Compounds, and Mixtures

This question tests your ability to distinguish between elements, compounds, and mixtures based on their composition and properties.

Key Terms:

• Element: A pure substance made of only one kind of atom.

• Compound: A substance formed when two or more elements are chemically bonded together.

• Mixture: A combination of two or more substances that are not chemically bonded.

Step-by-Step Guidance

1. Review the definitions of element, compound, and mixture.

2. Look at each answer choice and determine if it is made up of more than one element chemically combined.

3. Eliminate any answer that is a single element or a mixture.

Try solving on your own before revealing the answer!

Q3. Which of the following is an example of a mixture?

Background

Topic: Mixtures vs. Pure Substances

This question tests your ability to identify mixtures as opposed to pure substances (elements or compounds).

Key Terms:

• Mixture: Contains two or more substances physically combined.

• Homogeneous mixture: Uniform composition throughout.

• Heterogeneous mixture: Non-uniform composition.

Step-by-Step Guidance

1. Recall the definition of a mixture and how it differs from a pure substance.

2. Analyze each option to see if it contains more than one substance physically combined.

3. Eliminate any answer that is a single pure substance.

Try solving on your own before revealing the answer!

Q4. Which of the following statements regarding the solid state of matter is incorrect?

Background

Topic: Properties of Solids

This question tests your understanding of the characteristics of solids compared to other states of matter.

Key Terms:

• Solid: Definite shape and volume, particles closely packed.

• Liquid: Definite volume, indefinite shape.

• Gas: Indefinite shape and volume.

Step-by-Step Guidance

1. Review the properties of solids, such as particle arrangement and movement.

2. Read each statement carefully and compare it to what you know about solids.

3. Identify the statement that does not match the properties of solids.

Try solving on your own before revealing the answer!

Q5. An atom contains 1.50 × 1024 kg of sodium. What is this mass in units of grams?

Background

Topic: Unit Conversions (Metric System)

This question tests your ability to convert between kilograms and grams using metric prefixes.

Key Formula:

$1 \ \text{kg} = 1000 \ \text{g}$

Step-by-Step Guidance

1. Recall the conversion factor between kilograms and grams.

2. Multiply the given mass in kilograms by the conversion factor to get grams.

3. Set up the calculation as $\text{mass in grams} = \text{mass in kg} \times 1000$.

Try solving on your own before revealing the answer!

Q6. How many moles of Fe (iron) are in a can that contains 456 g?

Background

Topic: Moles and Molar Mass

This question tests your ability to convert mass to moles using the molar mass of iron.

Key Formula:

$\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}$

Key Term:

• Molar mass of Fe: Approximately 55.85 g/mol

Step-by-Step Guidance

1. Write down the mass of iron given in the problem.

2. Find the molar mass of iron from the periodic table.

3. Set up the calculation using the formula above.

Try solving on your own before revealing the answer!

Q7. The proprietor of a rock shop insists that a nugget is pure gold. If the nugget occupies a volume of 5.40 mL, what would its mass have to be if it were truly pure gold? (density of gold = 19.3 g/mL)

Background

Topic: Density Calculations

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

Key Formula:

$\text{Density} = \frac{\text{mass}}{\text{volume}}$

Rearranged: $\text{mass} = \text{density} \times \text{volume}$

Step-by-Step Guidance

1. Write down the given values: density and volume.

2. Plug the values into the rearranged density formula to solve for mass.

3. Set up the multiplication, but do not calculate the final value yet.

Try solving on your own before revealing the answer!

Q8. Which of the following is an example of a chemical property?

Background

Topic: Physical vs. Chemical Properties

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

Key Terms:

• Chemical property: Describes a substance's ability to undergo a specific chemical change.

• Physical property: Can be observed without changing the substance's identity.

Step-by-Step Guidance

1. Review the definitions of chemical and physical properties.

2. Analyze each option to see if it involves a chemical change (e.g., burning, rusting, decomposing).

3. Eliminate options that only involve physical changes (e.g., dissolving, melting).

Try solving on your own before revealing the answer!

Q9. The number 0.009525 correctly expressed in scientific notation is:

Background

Topic: Scientific Notation

This question tests your ability to convert a decimal number into scientific notation.

Key Formula:

$a \times 10^n$ where $1 \leq a < 10$ and $n$ is an integer.

Step-by-Step Guidance

1. Move the decimal point so that only one nonzero digit remains to the left of the decimal.

2. Count the number of places the decimal was moved; this determines the exponent.

3. If you move the decimal to the right, the exponent is negative.

Try solving on your own before revealing the answer!

Q10. 2.3 × 103 is equal to:

Background

Topic: Scientific Notation to Standard Form

This question tests your ability to convert a number from scientific notation to standard decimal form.

Key Formula:

$a \times 10^n$ means move the decimal point $n$ places to the right if $n$ is positive.

Step-by-Step Guidance

1. Identify the coefficient and the exponent in the scientific notation.

2. Move the decimal point in the coefficient to the right by the value of the exponent.

3. Write out the resulting standard number.

Try solving on your own before revealing the answer!

Q11. 56.256 g is rounded to how many significant figures?

Background

Topic: Significant Figures

This question tests your understanding of how to count significant figures in a measured quantity.

Key Terms:

• Significant figures: All nonzero digits, zeros between nonzero digits, and trailing zeros in the decimal part are significant.

Step-by-Step Guidance

1. Identify all nonzero digits in the number.

2. Count any zeros that are between nonzero digits or after the decimal point.

3. Add up all the significant digits.

Try solving on your own before revealing the answer!

Q12. Match the type of measurement to the unit given below.

Background

Topic: Units and Measurements

This question tests your knowledge of which units correspond to which types of measurements in chemistry.

Key Terms:

• cm3: Volume

• m: Distance

• Kilogram: Mass

• 273 K: Temperature

• grams/cm3: Density

Step-by-Step Guidance

1. Recall the SI unit for each type of measurement listed.

2. Match each unit to the correct measurement type.

Try solving on your own before revealing the answer!

Q13. Select the correct prefix to complete the equality: 1 g = ____ kg

Background

Topic: Metric Prefixes and Conversions

This question tests your understanding of metric prefixes and how to convert between grams and kilograms.

Key Formula:

$1 \ \text{kg} = 1000 \ \text{g}$

Step-by-Step Guidance

1. Recall the relationship between grams and kilograms.

2. Determine how many kilograms are in one gram by dividing by 1000.

Try solving on your own before revealing the answer!

Q14. 1 m = ____ cm; 1 cm = ____ mm

Background

Topic: Metric System Conversions

This question tests your ability to convert between meters, centimeters, and millimeters using metric prefixes.

Key Formula:

$1 \ \text{m} = 100 \ \text{cm}$

$1 \ \text{cm} = 10 \ \text{mm}$

Step-by-Step Guidance

1. Recall the metric prefixes for centi- (10-2) and milli- (10-3).

2. Use these relationships to fill in the blanks for each conversion.

Try solving on your own before revealing the answer!

Q15. How many seconds are there in 8.0 hours? (Express your final answer in seconds.)

Background

Topic: Dimensional Analysis (Unit Conversions)

This question tests your ability to convert between units of time using dimensional analysis.

Key Formula:

$1 \ \text{hour} = 60 \ \text{minutes}$

$1 \ \text{minute} = 60 \ \text{seconds}$

Step-by-Step Guidance

1. Start with the given value in hours.

2. Multiply by the conversion factor to change hours to minutes.

3. Multiply by the conversion factor to change minutes to seconds.

Try solving on your own before revealing the answer!

Q16. What is the density of a cube that has a mass of 100.0 g and is a cube that is 5.00 cm on each side? Will this object sink or float?

Background

Topic: Density Calculations and Buoyancy

This question tests your ability to calculate density and apply it to predict whether an object will sink or float in water.

Key Formula:

$\text{Density} = \frac{\text{mass}}{\text{volume}}$

Volume of a cube: $\text{side}^3$

Step-by-Step Guidance

1. Calculate the volume of the cube using the formula for the volume of a cube.

2. Plug the mass and calculated volume into the density formula.

3. Compare the density of the cube to the density of water (1.00 g/cm3) to predict if it will sink or float.

Try solving on your own before revealing the answer!

Q17. How many calories of energy are required to increase the temperature of 25 grams of water from 10°C to 50°C?

Background

Topic: Calorimetry (Heat Calculations)

This question tests your ability to use the specific heat formula to calculate the energy required to change the temperature of a substance.

Key Formula:

$q = m \cdot c \cdot \Delta T$

• $q$ = heat (calories)

• $m$ = mass (grams)

• $c$ = specific heat of water (1 cal/g°C)

• $\Delta T$ = change in temperature (°C)

Step-by-Step Guidance

1. Calculate the change in temperature ($\Delta T$) by subtracting the initial temperature from the final temperature.

2. Plug the values for mass, specific heat, and $\Delta T$ into the formula.

3. Set up the multiplication, but do not calculate the final value yet.

Try solving on your own before revealing the answer!

Q18. A 6-year-old was diagnosed with a sinus infection. She weighs 52.0 lbs. If the recommended pediatric dose of amoxicillin is 8.50 mg per kg, how many mg should she have in a day?

Background

Topic: Dosage Calculations and Unit Conversions

This question tests your ability to convert between pounds and kilograms and apply a dosage formula.

Key Formula:

$1 \ \text{kg} = 2.205 \ \text{lbs}$

Dosage (mg) = weight (kg) × recommended dose (mg/kg)

Step-by-Step Guidance

1. Convert the child's weight from pounds to kilograms using the conversion factor.

2. Multiply the weight in kilograms by the recommended dose per kilogram.

3. Set up the multiplication, but do not calculate the final value yet.

Try solving on your own before revealing the answer!