# Tutor profile: Michael B.

## Questions

### Subject: Chemistry

The valence or charge of an element can be the same as its oxidation state. In the reaction of magnesium with oxygen, the product is an oxide called magnesium oxide. How is the oxidation state of both elements different from their valence or charge?

Although the valence of magnesium as can be found in the periodic table is 2+ and oxygen is 2-, their oxidation states in the given chemical equation are both zero because the metal magnesium is in the free state and oxygen is a diatomic molecule. However, in magnesium oxide, the valence of magnesium is 2+ and oxygen is 2-. Hence, their difference.

### Subject: Physics

When a 10 gram object and a 20 gram object is dropped from a height, both object will reach the ground at the same time, ignoring air resistance. If the two objects were instead thrown upward, each with an initial velocity of 5 meters per second, which object will reach the ground first, ignoring air resistance?

Ignoring air resistance, both objects will reach the ground at the same time. To find out why, take a lesson with me.

### Subject: Algebra

The difference of two squares is a special product between the sum and difference of a binomial. Can you find the factors of the binomial (1 - x)?

By applying our knowledge in radicals, our factors are (1 - sqrt 2)(1 + sqrt 2) or in fractional exponent form we have (1 - x^1/2)(1 + x^1/2).

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