Matter Packet Computer Science Code.Org - Laliberte, 7/17 ... - Free Printable

It looks like you've uploaded a chemistry worksheet titled "Chemistry Worksheet: Matter #1," which contains questions about the classification of matter, elements, compounds, mixtures, and separation techniques.

Let me go through each question and provide clear answers with explanations. Here's the solution:

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1. A mixture (like water) is a chemical combining of substances.
✘ False

✔ Explanation: A mixture is not a chemical combining of substances. In a mixture, substances are physically combined and can be separated by physical means. No new chemical bonds are formed. For example, saltwater is a mixture where salt and water are not chemically bonded.

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2. The smallest unit that makes up an element is called an atom.
✔ True

✔ Explanation: An atom is the smallest unit of an element that retains the chemical properties of that element. For example, a single oxygen atom (O) is the smallest particle that is still oxygen.

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3. The smallest identifiable unit of a compound is a molecule.
✔ True

✔ Explanation: A molecule is the smallest unit of a compound that retains its chemical properties. For example, a water molecule (H₂O) consists of two hydrogen atoms and one oxygen atom chemically bonded together.

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4. True or False: A mixture is always made up of a combination of elements.
✘ False

✔ Explanation: A mixture can consist of elements, compounds, or both. For example, air is a mixture of nitrogen gas (N₂), oxygen gas (O₂), and carbon dioxide (CO₂)—a mix of elements and compounds.

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5. In a mixture, the substances (elements/compounds) keep their identity.
✔ True

✔ Explanation: In a mixture, no chemical reaction occurs, so each substance maintains its own physical and chemical properties. For instance, in saltwater, salt (NaCl) and water (H₂O) remain distinct substances.

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6. In a mixture the substances involved (combined) are separated by a simple physical process.
✔ True

✔ Explanation: Mixtures can be separated using physical methods such as filtration, evaporation, distillation, etc., because the components are not chemically bonded.

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7. True or False: An element can be broken down into a simpler substance.
✘ False

✔ Explanation: Elements cannot be broken down into simpler substances by chemical means. They are made of only one type of atom. For example, oxygen (O₂) is an element and cannot be chemically broken down further into simpler substances.

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8. The smallest identifiable unit of an element is also called an atom.
✔ True

✔ Explanation: As stated earlier, the smallest unit of an element that retains its properties is an atom.

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9. From the following list of substances, circle the ones that are elements:
- hydrogen → ✔ Element
- carbon dioxide → ✘ Compound
- sugar → ✘ Compound
- oxygen → ✔ Element
- chromium → ✔ Element
- aluminum → ✔ Element
- salt → ✘ Compound (NaCl)
- potassium → ✔ Element

✔ Elements: hydrogen, oxygen, chromium, aluminum, potassium

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10. Explain how to separate a sugar and water solution.
✔ Answer: You can use evaporation. Heat the solution gently. Water will evaporate, leaving behind solid sugar. This works because sugar does not evaporate at the same temperature as water.

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11. How would you separate a mixture of alcohol and water?
✔ Answer: Use distillation. Alcohol (ethanol) boils at a lower temperature (78°C) than water (100°C). By heating the mixture, ethanol vaporizes first and can be condensed and collected separately.

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12. How would you separate sand and water?
✔ Answer: Use filtration. Pour the mixture through filter paper. Water passes through, while sand remains on the filter paper.

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Summary of Answers:

1. False
2. True
3. True
4. False
5. True
6. True
7. False
8. True
9. Hydrogen, oxygen, chromium, aluminum, potassium
10. Evaporation
11. Distillation
12. Filtration

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