Chebyshev's Inequality and CLT

Question

I am very confused as to how to approach questions 2 and 3 and the example problems in my notes don't have this specific problem structure. Any help would be great, here is the question below:

Suppose we want to estimate the pH of a mysterious liquid. Let the true pH be 5. We take n readings and let Xi be the value returned by the ith reading. You should assume the readings are independent and that $E[X_i] = 5$ and var$[X_i] = 2$. Let $Y = \frac{1}{n}(X_1 + X_2 + \dotsb + X_n)$ be the average of these readings.

1. Find out the mean and variance of $Y$ .
2. How large does $n$ need to be such that $P(4.9 < Y < 5.1) ≥ 0.99$ using the Chebyshev’s inequality?
3. How large does n need to be such that $P(4.9 < Y < 5.1) ≥ 0.99$ using the Central Limit Theorem?