Question

q20. what happens when you mix cold water and warm water? *
they begin to mix immediately
cold water rises before they mix
warm water rises before they mix
cold water will push the warm water to the bottom
q21. you measured the mass of an empty graduated cylinder using a balance, and it was 22.5 grams. and then you poured a liquid in the graduated cylinder, and the mass became 26.7 grams. how do you calculate the mass of the liquid?
22.5 multiply by 26.7

Explanation:

Q20

Warm water is less dense than cold water. Less - dense substances rise in a fluid medium. So warm water rises before they mix.

Step1: Identify the principle

The mass of the liquid is the total mass (cylinder + liquid) minus the mass of the empty cylinder.

Step2: Substitute values

Let $m_{empty}=22.5$ g and $m_{total}=26.7$ g. The mass of the liquid $m = m_{total}-m_{empty}$.
$m=26.7 - 22.5$

Answer:

C. Warm water rises before they mix

Q21