Answer:
D.
Explanation:
Adding more gas particles to a set volume will increase the number of collisions, thus increasing collision force and pressure.
Answer:
24.09 grams of chlorine gas reacted.
Explanation:

Moles of sodium chloride = 
According to reaction, 2 moles of NaCl are formed from 1 mole chlorine gas.
Then 0.6786 moles of NaCl will be formed from;

Mass of 0.3393 moles of chlorine gas:
0.3393 mol × 71 g/mol = 24.09 g
24.09 grams of chlorine gas reacted.
Helium is a chemical element of the atomic number 2, an inert gas that is the lightest member of the noble gas series.
These means, Helium is lighter than air, and for this is why all other balloons may not float.
The helium balloon displaces an amount of air (Just like an empty water bottle displaces an amount of water). As long as the weight of the helium plus the balloon fabric is lighter than the air displaces, the balloon will float in the air.
Answer:
Normally, it explains that matter cannot be created or destroyed. It demonstrates different chemical reactions that help show the different transformations of the matter but will never destroy it or create it.