# Tutor profile: Madeleine V.

## Questions

### Subject: Chemistry

What volume of 1.5M NaOH is needed to provide 0.75 mol of NaOH? (a) 500L (b) 5.0 L (c) 500 mL (d) 0.75 L

M represents moles per liter, so the goal is to identify the volume of the concentrated solution (1.5M NaOH) that would contain just 0.75 moles of NaOH. We can easily translate the language in the question to: 0.75 moles is contained in what volume of 1.5M NaOH OR 0.75 = x (unknown volume) x 1.5M Then, X = (0.75moles)/(1.5M) After units cancel out, you are left with 0.5 Liters, which is equivalent to 500mL Answer: C

### Subject: Biology

Which of the following levels of organization is NOT matched with the appropriate structure in the human body? A. tissue : epithelium B. organ : liver C. tissue : nerve D. organ : skin E. tissue : stomach

This question is asking about levels of organization in the body. From most basic to most complex is the following: cells --> tissues --> organs. This is an important concept in biology, as understanding physiology is based on this concept!

### Subject: Algebra

Evaluate: 11 + sqrt(-4 + 6×4÷3)

According to the PEMDAS mnemonic, solve inside parentheses first: (-4+6x4÷3) 1. E: exponents: none 2. M: multiplication: 6x4 = 24 This gives you: (-4+24÷3) 3. D: Division: 24÷3 = 8 This gives you: (-4+8) which = +4 4. Take the square root of +4 = 2 5. Add 11+2 = 13