Chem 1151 Chapter 2 Part 2

What is the formula for calculating specific gravity?

• Specific Gravity = Weight of Substance / Weight of Water

• Specific Gravity = Density of Substance / Density of Water

• Specific Gravity = Mass of Substance / Volume of Water

• Specific Gravity = Density of Water / Density of Substance

Define a pure substance and give two examples.

• Sugar (C12H22O11), Mercury (Hg)

• Air (N2, O2), Iron (Fe)

• Salt (NaCl), Silver (Ag)

• Water (H2O), Gold (Au)

What distinguishes a homogeneous mixture from a heterogeneous mixture?

• A homogeneous mixture has different components, while a heterogeneous mixture has a uniform composition.

• A homogeneous mixture has a uniform composition, while a heterogeneous mixture has visibly different components.

• A homogeneous mixture is always a solid, while a heterogeneous mixture is always a liquid.

• A homogeneous mixture can be separated by physical means, while a heterogeneous mixture cannot.

List the three main states of matter and one property of each.

• 1. Solid: Definite shape; 2. Liquid: Definite volume; 3. Gas: No definite shape or volume.

• Liquid: Takes the shape of its container.

• Solid: Flows easily;

• Plasma: No definite shape;

What unit is commonly used to measure temperature in scientific contexts?

• Kelvin

• Fahrenheit

• Rankine

• Celsius

Explain the concept of specific heat and its significance in energy transfer.

• Specific heat is crucial for understanding energy transfer as it quantifies how substances absorb and release heat.

• Specific heat is the same for all substances.

• Specific heat only applies to gases, not liquids or solids.

• Specific heat measures the weight of a substance.

How does the specific gravity of a substance relate to its density?

• Specific gravity is the ratio of a substance's density to the density of water.

• Specific gravity is the density of a substance multiplied by the density of water.

• Specific gravity is the same as mass.

• Specific gravity measures the weight of a substance in air.

Provide an example of a heterogeneous mixture and explain why it is classified as such.

• A smoothie

• A bowl of rice

• A salad

• A glass of water

What happens to the particles of a substance during a change of state?

• Particles gain or lose energy, affecting their movement and arrangement.

• Particles are destroyed and replaced by new ones.

• Particles change color but not their energy levels.

• Particles become solid and stop moving completely.

Describe the process of melting and the energy changes involved.

• Melting occurs without any change in temperature.

• Melting is the transition from solid to liquid, involving the absorption of energy to overcome intermolecular forces.

• Melting requires the release of energy to form a solid.

• Melting is the process of freezing water into ice.