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Atoms to Mixtures Exploration

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Atoms to Mixtures Exploration

Use the particle key and the sample models to investigate how atoms form molecules, compounds, and mixtures. Answer each question; for the model task, use circles and labels to show particles.

Particle Key and Sample Models

Each letter represents one atom. A line between letters means the atoms are bonded. A space between groups means they are not bonded to each other.

Sample A: H—H H—H H—H All particles are identical pairs of hydrogen atoms.

Sample B: H—O—H H—O—H Each particle has two hydrogen atoms bonded to one oxygen atom.

Sample C: H—H O—O H—H O—O Two kinds of particles are present, but each particle contains only one kind of atom.

Sample D: H—O—H H—H O—O Different kinds of particles are together in one sample.

Analyze the Samples

1.Using the written particle model for Sample B, identify the smallest unit that represents water. How many atoms does it contain, and how many different elements are in it?

2.Which sample is a pure element made of molecules? Choose the best answer.

Sample A only
Sample B only
Samples A and B
Samples C and D

3.Which sample is a compound? Explain how the particle model supports your choice.

4.True or false: Sample C is a compound because it contains both hydrogen and oxygen atoms. Correct the statement if it is false.

TrueFalse

5.Complete the comparison: Sample D is a , while Sample B is a . Use the terms “mixture” and “pure substance.”

6.A lab partner says, “Every molecule is a compound.” Use Sample A or B to show why this statement is not always correct.

Atoms, Molecules, and Living Things

Atoms can bond into molecules, and molecules can take part in building larger biological structures. For example, amino acids are small molecules that link together to make proteins. Proteins are not simply one large molecule of a single repeated atom; they are complex molecules made from many atoms.

7.Put these distinct levels in order from smallest to largest: protein, atom, amino acid. Write the sequence and explain how amino acids relate to molecules.

8.Why are amino acids important to living organisms? Choose the best answer.

They are the building blocks that link together to form proteins.
They are atoms that cannot form bonds.
They make every mixture a compound.
They are found only in nonliving matter.

9.Model a mixture containing hydrogen molecules (H₂) and water molecules (H₂O). Draw at least two of each particle, keep atoms bonded within each molecule, and add a key identifying H and O.

10.A sealed sample contains only water molecules, each made of hydrogen and oxygen. Is it a pure substance, a mixture, an element, or a compound? It may fit more than one description; explain.