# Tutor profile: Christian B.

## Questions

### Subject: Writing

In writing the questions would usually be to proofread an essay and I don't think it would be feasible for me to write an essay with mistakes and then proofread it myself.

See question above.

### Subject: Basic Chemistry

How many grams of Na3PO4 are required to make 412 mL of a 1.50 M solution? (Use the unit g)

First calcuate the moles using Moles = [conc] x Vol(mL) / 1000 mol = 1.5 x 412 / 1000 mol = 0.618 moles of Na3PO4 is required. Next calculate the Mr of Na3PO4 Na x 3 = 23 x 3 = 69 P x 1 = 31 x 1 = 31 O x 4 = 16 x 4 = 64 69 + 31 + 64 = 164 Using the the eq'n moles = mass(g) / Mr mass = 0.618 x 164 = 101.352 g So to the nearest gram you require 101 g. of solid sodium phosphate.

### Subject: Algebra

Solve 5(-3x - 2) - (x - 3) = -4(4x + 5) + 13

Multiply factors. -15x - 10 - x + 3 = -16x - 20 +13 Group like terms. -16x - 7 = -16x - 7 Add 16x + 7 to both sides and write the equation as follows 0 = 0 The above statement is true for all values of x and therefore all real numbers are solutions to the given equation.

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