1. Your school science project is titled, “Atoms vs Molecules”. Your partner thinks the picture of ammonia should go on the atom side. Justify why ammonia belongs on the molecule side of the poster, using at least two pieces of evidence from the question. Be sure to discuss what atoms are in your model and how they form a molecule of ammonia.

2. Observing an atom of ammonia before and after its formation, The Law of Conservation of Mass would support .

3. Is it accurate for the student models to show the nitrogen atom and hydrogen atoms as different sizes?

• Yes, because the nitrogen nucleus contains more protons and neutrons, and there are more orbitals to hold nitrogens electrons.
• No because all gas atoms are exactly the same size; only liquid and solid atoms vary.
• No, all atoms should be represented as being the same size because that is not what they are studying in their model
• Yes because nitrogen is a much heavier gas than hydrogen.

4. Gaseous ammonia has a much stronger smell than liquid ammonia. Explain how your model in the last question can be used to explain why this is.

5. At really high temperatures ammonia molecules can start to break apart and form molecules of hydrogen (H2) and nitrogen (N2). Create a model to predict how hydrogen and nitrogen molecules differ from ammonia.

6. The two molecules that connect to each other in Ammonia Hydroxide are and .

7. In the space below, draw an image of an ammonia molecule. Be sure to label the atoms.

8. The students were asked to compare their models of NH3 to molecular models of hydronium which has the chemical formula (H3O). Which statement best describes how these molecular models would compare?

• The nitrogen atom in NH3 would be replaced with three atoms of oxygen in H3O, but the atoms of hydrogen would be the same.
• None of the atoms would be the same between the molecules, but there would be the same number of bonds holding the molecules together.
• There are still 4 total atoms in each compound, 3 of those atoms being hydrogen.
• Instead of three hydrogen atoms like in NH3, there would be three oxygen atoms in H3O.

9. Explain what atoms are in your model and how they form a molecule of ammonia.

10. Is it accurate for the student models to show the nitrogen atom and hydrogen atoms as different sizes?

• No, because atoms of different elements are all typically about the same size.
• Yes, because atoms of different elements can differ in size, but atoms of the same element are about the same size.
• Yes, because atoms vary a lot in size based on how many of each element is present in the molecule.
• No, because hydrogen atoms and nitrogen atoms are the same element so they should be the same size.

11. The students that created the provided models are asked to predict how their model would change if the structure was NH4 instead of NH3, which student revision accurately shows this change?

• Kyle: “I would bond another hydrogen to the center nitrogen atom of my model”
• Freddy: “I would add another hydrogen to the existing chain of hydrogens in my model”
• Tiffany: “I would add a hydrogen in the center of my model where all the bonds connect”
• Kyle: “I would bond another hydrogen off one of the existing hydrogens in my model”

12. In the space below, draw a model of a water molecule (H20) that the ammonia will react with to form ammonia hydroxide.

13. How does the scale of the student models provided compare?

• Tiffany’s model shows the largest scale because her model shows the most bonds between atoms in an ammonia molecule.
• The models all show the same scale of the atoms that make up a molecule of ammonia.
• Freddy and Kyle’s models show a similar scale which shows how molecules of ammonia interact.
• The models all show the same scale of how multiple molecules in a sample of ammonia are bonded.

14. Ammonia gas contains particles that are and .

15. Oxygen gas (O2) is in some ways similar to ammonia gas, but also has some differences. Which statement best describes how their molecular models would compare?

• Both models would contain molecules that are attracted to each other in a large structure, but oxygen would contain only one type of atom and ammonia would contain two different types of atoms.
• Both models would contain molecules not attracted to each other, but oxygen would contain only one type of atom and ammonia would contain two different types of atoms.
• Both models would contain the same size molecules, but the ammonia molecules would be attracted to each other more than oxygen molecules would.
• Both models would contain the same types of atoms, but the oxygen molecules would be more attracted to each other than the ammonia molecules would be.

16. Explain what atoms are found in your model and how they come together to form a molecule.

17. Which of the following is an observable physical property of ammonia gas?

• Pressure
• Particle size
• Strong odor
• Hardness

18. What atom(s) is/are present in ammonia?

• NH
• N and H
• N and H3
• NH3

19. Consider the student models provided. How could the model that is correct be revised to better communicate bulk scale differences between ammonia gas and ammonia liquid?

• There would need to be less bonds holding the atoms together.
• There would need to be more than one molecule of ammonia shown in the models.
• There would need to be different types of atoms shown in the molecules.
• There would need to be more bonds holding multiple molecules together.

20. Draw a model of the combination of Water (H₂0) and Ammonia (NH₃) molecules to form Ammonia Hydroxide (NH₄OH).

21. Why do all the student models show the nitrogen atom and hydrogen atoms as different sizes?

• Hydrogen is the biggest atom in the periodic table and bonds with nearly every other atom.
• Hydrogen has a smaller nucleus than nitrogen, which means it has the space to bond with more atoms.
• Nitrogen has a larger nucleus than hydrogen and more electrons that can bond with other atoms.
• Nitrogen is drawn bigger because it has more electrons and a smaller nucleus than hydrogen.

22. When ammonia (NHreacts with water (H2O) it forms a new liquid substance called ammonium hydroxide (NH4OH). Which statement describes how a model of ammonium hydroxide would be different from a model of ammonia?

• Ammonium hydroxide molecules would be more spread out from each other because they are made of more complex atoms than ammonia molecules.
• Ammonium hydroxide molecules would form an extended structure that connects molecules together in one unit and ammonia doesn’t.
• Ammonium hydroxide molecules have more atoms of hydrogen and oxygen which would make the structure larger than molecules of NH3.
• Ammonium hydroxide molecules would look the same as ammonia molecules, but they would be clustered together more since they are liquid.

23. Explain how your model shows that Water and Ammonia can become Ammonia Hydroxide.

24. Which of the following observations could be used as evidence that gases invisible to the naked eye are made of particles?

• Gases can be observed turning into other forms, like condensation on a glass
• Gases can cause objects to move, like the wind blowing open a door
• All of these can be used as evidence
• Gases can take up space, like filling the inside of a balloon

25. Your teacher asks your class how the student models represent that ammonia is a molecule and not an atom. Which student provides the best answer?

• Kennedy: “The models show each atom is a different element by putting the symbol inside the circle”
• Teddy: “The models use three circles to represent hydrogen and one circle to represent nitrogen”
• Lionel: “The models show different atoms bonded together with lines to form one connected structure”
• Beau: “The models use lines to connect each molecule together”

26. Substances that are made of different atoms can have different that are used to identify them.

27. Create a model that shows two samples of ammonia (NH3), one sample that is a gas and one that is a liquid.

28. One difference between ammonia gas and liquid ammonia is the ?

29. A container filled with ammonia is being transported and contains 5L of liquid ammonia. Which statement describes what is in the container?

• A lot of ammonia molecules that connect together in an extended structure
• A lot of molecules of nitrogen and hydrogen that move around freely
• A lot of individual ammonia molecules that move around freely
• A lot of atoms of nitrogen and hydrogen, and some of them are bonded together to form NH3

30. If we compared the atoms before the formation of ammonia and after, we would see that .

31. Is it accurate for the student models to show the nitrogen atom and hydrogen atoms as different sizes?

• Yes, because the nitrogen nucleus contains more protons and neutrons, and there are more orbitals to hold nitrogens electrons.
• Yes because nitrogen is a much heavier gas than hydrogen.
• No, all atoms should be represented as being the same size because that is not what they are studying in their model
• No because all gas atoms are exactly the same size; only liquid and solid atoms vary.

32. Explain what would cause water to behave in a way so that it ends up in the air to react with ammonia and not be found as a liquid.