# Tutor profile: Marissa H.

## Questions

### Subject: Chemistry

4Al + 3O2 → xAl2O3. Find 'x'

We can think of this as a typical equation, where one side of the equal sign (or arrow in this case) has to be equal. We first count what is on the left side and can make an inventory of each element. On the left, there is 4 aluminum and 6 oxygens. That is because oxygen exists in a pair in its natural form and there are 3 of those molecules, making 6 total atoms. Thus, we know that the right side needs 4 aluminum and 6 oxygen as well. The only coefficient that would work would be 2 since each molecule has 2 aluminum and 3 oxygen. Thus x=2

### Subject: Biology

describe the function and path of ions through the Na/K atpase pump

The Na/K ATPase pump's primary physiological role is the maintenance of large gradients, inward for sodium (Na+) and outward for potassium (K+), across the plasma membrane of all animal cells. An easy acronym to remember the direction and number of ions pumped is 321 Nokia where 3 sodium ions (Na) are pumped out, 2 potassium ions (K) are pumped in, and 1 ATP is used.

### Subject: Algebra

2(x - 3) = 4x - 1 solve for x

I would first begin by asking them what the problem is asking them to do and then would ask them to explain how they would solve it. 1. Problem is asking for us to solve for x 2. The parenthesis requires us to distribute 3. I would multiply everything on the left by 2 2x-6=4x-1 4. Now I isolate x onto one side by subtracting 2x for both sides (what you do to one side, you must do to the other) since I want the variable to stay positive -6 = 2x -1 5. Now i would add 1 to both sides to get x by itself -5 = 2x 6. Now i divide both sides by 2 to get x alone x = -5/2

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