Question

topic 2: mixtures and separation
study guide

• mixture: combination of substances, not chemically bonded.
• homogeneous: uniform (ex: salt water).
• heterogeneous: not uniform (ex: salad).
• separation methods: filtration, evaporation, distillation, chromatography, magnet.

activities

1. multiple choice: which method best separates sand and salt - water?

a) filtration b) evaporation c) magnet d) chromatography
answer:

1. fill - in - the - blank: a mixture that looks the same throughout is
2. sorting: circle homogeneous mixtures: salt water trail mix kool - aid pizza
3. matching:

• coffee filter →
• evaporation dish →

(choices: filtration / evaporation)

1. short answer: why cant filtration separate oil and water?
2. mini - experiment: how would you separate salt, iron filings, and water?

topic 3: pure substances vs. mixtures
study guide

• matter → pure substance or mixture
• pure substances: elements (one type of atom) and compounds (atoms bonded).
• mixtures: physical blends; can be homogeneous or heterogeneous.
• difference: compounds have fixed ratios; mixtures do not.

activities

1. concept map starter: fill in blanks:

matter → ____________+____________
pure substances → ____________+____________
mixtures → ____________+____________

1. multiple choice: which is a pure substance?

a) salt water b) aluminum c) air d) trail mix
answer:

1. true/false: compounds are mixtures of two or more elements.

Explanation:

Step1: Answer question 1

Sand is insoluble in water and has a larger particle - size. Filtration can separate solid - liquid mixtures where the solid is insoluble. So the answer is a) Filtration.

Step2: Answer question 2

A homogeneous mixture has a uniform composition throughout. So the answer is "homogeneous".

Step3: Answer question 3

Salt water and Kool - Aid are homogeneous mixtures as they have a uniform composition. Trail mix and pizza are heterogeneous.

Step4: Answer question 4

A coffee filter is used for filtration. An evaporation dish is used for evaporation. So Coffee filter → Filtration; Evaporation dish → Evaporation.

Step5: Answer question 5

Filtration separates based on particle size and solubility. Oil and water are both liquids and form a heterogeneous liquid - liquid mixture. They are immiscible but not separable by filtration as both can pass through the filter paper pores.

Step6: Answer question 6

First, use a magnet to separate the iron filings as iron is magnetic. Then, evaporate the water to separate the salt from the remaining water - salt mixture.

Step7: Answer topic 3 question 1

Matter → Pure Substance + Mixture; Pure Substances → Elements + Compounds; Mixtures → Homogeneous Mixtures + Heterogeneous Mixtures

Step8: Answer topic 3 question 2

Aluminum is an element and thus a pure substance. Salt water is a mixture, air is a mixture, and trail mix is a mixture. So the answer is b) Aluminum.

Step9: Answer topic 3 question 3

Compounds are pure substances with atoms bonded in a fixed ratio, not mixtures. So the answer is False.

Answer:

1. a) Filtration
2. homogeneous
3. Salt water, Kool - Aid
4. Coffee filter → Filtration; Evaporation dish → Evaporation
5. Oil and water are both liquids and both can pass through filter paper pores as they are not separated by particle - size differences relevant to filtration.
6. Use a magnet to separate iron filings first, then evaporate water to get salt.

Topic 3:

1. Matter → Pure Substance + Mixture; Pure Substances → Elements + Compounds; Mixtures → Homogeneous Mixtures + Heterogeneous Mixtures
2. b) Aluminum
3. False