PhET Activity for MS-PS1-5: Reactants, Products and Leftovers

DIRECTIONS:
1. You should be on the 'Sandwiches' tab with the 'Cheese' reaction selected.
2. Locate the 'Before Reaction' box and the 'Reactants' controls below it.
3. Click the up arrow on the 'bread' stepper twice to add 2 slices of bread.
4. Observe the 'Before Reaction' and 'After Reaction' boxes.
5. Now, click the up arrow on the 'cheese' stepper once to add 1 slice of cheese.
6. Observe how the 'After Reaction' box changes.
7. Click the orange 'Reset Button' in the bottom right corner to clear everything.
Spend 2-3 minutes exploring the 'Sandwiches' tab. Try selecting the 'Meat and Cheese' and 'Custom' reactions. Use the steppers to add different amounts of ingredients and see what happens. Reset the simulation before moving to the next slide.

QUESTION: Are you acquainted with the tools in this simulation?

DIRECTIONS:
1. Ensure you are on the 'Sandwiches' tab with the 'Cheese' reaction selected. If not, click the 'Cheese' radio button in the top right panel.
2. Make sure the simulation is reset, with all counts at zero.
3. Using the steppers at the bottom left, set the 'bread' count to 2.
4. Set the 'cheese' count to 1.

QUESTION: When you combine exactly 2 slices of bread and 1 slice of cheese, what is the result in the 'After Reaction' box?

DIRECTIONS:
1. Do not reset the simulation. You should have 2 bread and 1 cheese, resulting in 1 sandwich.
2. Click the up arrow on the 'bread' stepper one more time to change the bread count to 3.

QUESTION: With 3 bread slices and 1 cheese slice, the reactants are bread and cheese. The product is the sandwich. The item that did not get used up is called the (a)   .

DIRECTIONS:
1. Click the orange 'Reset Button' in the bottom right corner.
2. Set the 'bread' count to 5.
3. Set the 'cheese' count to 1.

QUESTION: In this scenario, the reaction stops because you ran out of (a)   . This makes it the limiting reactant.

DIRECTIONS:
1. Click the orange 'Reset Button' in the bottom right corner.
2. Set the 'bread' count to 2.
3. Set the 'cheese' count to 4.

QUESTION: Why can you only make one sandwich, even though you have 4 slices of cheese?

DIRECTIONS:
1. Click the 'Meat and Cheese' radio button in the top right panel. This will reset the reaction.
2. Set the 'bread' count to 2.
3. Set the 'meat' count to 1.
4. Set the 'cheese' count to 1.

QUESTION: To make one 'Meat and Cheese' sandwich, you need ___ bread slices, ___ meat slice, and ___ cheese slice. In this reaction, there are no ___.

(a)  

DIRECTIONS:
1. Click the 'Molecules' tab at the bottom of the screen.
2. The simulation will likely default to the 'Make Ammonia' reaction. Click the 'Make Water' radio button in the top right panel.
3. Observe the balanced chemical equation at the top: 2 H₂ + 1 O₂ → 2 H₂O.

QUESTION: In your own words, describe one key similarity and one key difference between the 'Sandwiches' tab and the 'Molecules' tab.

DIRECTIONS:
1. Ensure you are on the 'Molecules' tab with the 'Make Water' reaction selected and all counts at zero.
2. Set the H₂ reactant count to 2.
3. Set the O₂ reactant count to 1.

QUESTION: Which statement accurately describes the atoms before and after the reaction?

DIRECTIONS:
1. Do not reset. You should have 2 H₂ and 1 O₂ as reactants, forming 2 H₂O.
2. Use the stepper to increase the O₂ reactant count to 2.

QUESTION: When you have 2 H₂ and 2 O₂ as reactants, the 'After Reaction' box shows 2 H₂O molecules and 1 leftover (a)   molecule.

DIRECTIONS:
1. Click the orange 'Reset Button'.
2. Click the 'Make Ammonia' radio button in the top right panel.
3. Set the N₂ reactant count to 1.
4. Set the H₂ reactant count to 3.

QUESTION: In the reactants, there are ___ nitrogen atoms and ___ hydrogen atoms. In the products, there are ___ nitrogen atoms and ___ hydrogen atoms.

(a)