Q1. A combination of two or more substances that can be separated by using only a physical process is:

Background

Topic: Classification of Matter

This question tests your understanding of mixtures, compounds, elements, and substances, and how they are separated.

Key Terms:

• Mixture: A physical combination of two or more substances.

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

• Element: A pure substance consisting of only one type of atom.

• Substance: Matter with a uniform and definite composition.

Step-by-Step Guidance

1. Recall the definitions of mixture, compound, element, and substance.

2. Consider which of these can be separated by physical means (like filtration, distillation, etc.).

3. Think about whether compounds or elements can be separated by physical processes, or if they require chemical changes.

Try solving on your own before revealing the answer!

Q2. The correct answer for the addition 102.5 mL + 6.35 mL is: (considering significant figures)

Background

Topic: Significant Figures

This question tests your ability to add numbers and report the answer with the correct number of significant figures.

Key Terms and Formula:

• Significant Figures: Digits in a number that are meaningful in terms of accuracy.

• When adding, the answer should have the same decimal places as the measurement with the least decimal places.

Step-by-Step Guidance

1. Write both numbers: 102.5 mL (1 decimal place), 6.35 mL (2 decimal places).

2. Add the numbers together.

3. Determine which number has the least decimal places.

4. Round your sum to match the least number of decimal places.

Try solving on your own before revealing the answer!

Q3. A 25 g cube will sink in hexane, but float in water. Place these three substances in order from least density to greatest density.

Background

Topic: Density and Buoyancy

This question tests your understanding of density and how it affects whether an object sinks or floats.

Key Terms:

• Density ():

• Buoyancy: An object floats if its density is less than the liquid's density.

Step-by-Step Guidance

1. Recall that an object floats in a liquid if its density is less than the liquid's density.

2. The cube floats in water, so its density is less than water's density.

3. The cube sinks in hexane, so its density is greater than hexane's density.

4. Arrange hexane, cube, and water from least to greatest density based on these observations.

Try solving on your own before revealing the answer!

Q4. If the density of a certain alcohol is 0.785 g/mL, what mass of the alcohol would have a volume of 200.0 mL?

Background

Topic: Density Calculations

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

Key Formula:

• = density (g/mL)

• = mass (g)

• = volume (mL)

Step-by-Step Guidance

1. Write the density formula:

2. Rearrange to solve for mass:

3. Plug in the values: g/mL, mL.

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

Try solving on your own before revealing the answer!

Q5. A can of soup has a mass of 18.75 ounces. What is this mass in kg? (16 ounces = 453.6 g)

Background

Topic: Unit Conversion

This question tests your ability to convert between units (ounces to grams, then grams to kilograms).

Key Formula:

• Conversion factor: $16= 453.6$ g

• $1= 1000$ g

Step-by-Step Guidance

1. Set up the conversion from ounces to grams using the given factor.

2. Calculate the mass in grams (do not compute the final value yet).

3. Convert grams to kilograms by dividing by 1000.

4. Set up the final calculation for mass in kg.

Try solving on your own before revealing the answer!