# Tutor profile: Christine D.

## Questions

### Subject: Basic Chemistry

Which answer includes all the following that are chemical changes and not physical changes? I. freezing of water II. rusting of iron III. dropping a piece of iron into hydrochloric acid (H2 is produced) IV. burning a piece of wood V. emission of light by a kerosene oil lamp

First we need to know the definition of chemical change and physical change. A physical change refers to a change in the state of matter, i.e. evaporation of a liquid to a gas. The chemical compound does not change. A chemical change refers to the breakdown of a substance or the reaction between two substances that makes a new chemical compound. Now looking back at the answers, let's categorize each on. I. Freezing of water - physical change II. Rusting of Iron - chemical change III. dropping a piece of iron into hydrochloric acid (H2 is produced) - chemical change IV. Burning a piece of wood - chemical change V. Emission of light by a kerosene oil lamp- chemical change Therefore the answer is II, III, IV, and V

### Subject: Anatomy

How may compartments are there in the lower leg, and what nerve innervates each one?

There are 4 compartments. 1. Anterior Compartment, Deep Peroneal/Fibular Nerve 2. Lateral Compartment, Superficial Peroneal/Fibular Nerve 3. Superficial Posterior, Tibial Nerve 4. Deep Posterior, Tibial Nerve

### Subject: Algebra

Please simplify the following equation: 4 ( 3x - ( 9 - 6y + 2x) + 3y)

For this equation we must remember our order of operations: 1. Parentheses 2. Exponents 3. Multiplication and Division 4. Addition and Subtractions. Let's take the equation step by step. - We can multiply the 4 throughout the equation to start, since we cannot simplify the current parenthesis and we have no exponents. 12x - (36 - 24y + 8x) + 12y - We now need to distribute the -1 that is in front of the remain parentheses. Remember that negative sign is the same as having -1 to multiply. 12x - 36 +24y - 8x + 12y - We can now simply with addition and subtraction of the same variables. 12x - 8x = 4x 24y + 12y = 36 y - Our final answer is: 4x+36y-36 Always remember to (P)lease (E)xcuse (M)y (D)ear (A)unt (S)ally. Or, (P)arentheses, (E)xponents (M)ultiplication (D)ivision (A)ddition (S)ubtraction

## Contact tutor

needs and Christine will reply soon.