THIS IS A SCIENCE QUESTION Which choice describes how temperature differences affect air?

A. Hot air rises, and cold air sinks.

B. Hot air sinks, and cold air rises.

C. Hot air is steady, and cold air moves fast.

D. Hot air moves fast, and cold air rises.

What is the ph of a solution with a 1.50 × 10−9 m hydroxide ion concentration?

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Abeaker with 2.00×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 4.70 ml of a 0.360 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.