About 4. the weight of He is about 4 amus and the weight of O is about 16 amus, so you would need 4 He atoms to get close to the same mass as an O atom. i hope this helps
Answer: oxidizes in air
Explanation: Chemical property is the property which deals with change in chemical composition of the substance.
Physical change is the property which deals with change in physical state of the substance.

The above equation represents the oxidation of methane to form carbon dioxide and water. Thus the chemical composition has changed and is a chemical property.
Color and odor only involves no change in chemical composition.
<u>The forces between molecules are much stronger than the forces between ions.</u>
➜ True
Only the oxygen part of the atmosphere participates in the burning of candle wax.
When the candle is burning, the wick burns and the heat generated from burning melts the wax. The liquid wax serves as a fuel that sustains the burning of the wick.
The candle wax is a hydrocarbon. Hydrocarbon compounds are generally known to burn is oxygen to produce carbon dioxide and water.
Thus, the candle wax burns in the oxygen component of the air to produce carbon dioxide and water as by-products. All other components of air do not participate in the system.
More on burning can be found here: brainly.com/question/18199161?referrer=searchResults
Ba+H↓2O⇒BaO+H↓2O
You'll have to divide 25.0g by the formula mass of barium and then compare the mole ratio in your formula.
PV=nRT Rearranged is: V=nRT/P
V=volume=? n=moles of H2 P=pressure 748mmhg
R=universal gas constant (62.3638L×mmHg/K×mol)
T =temperature(21+273.15=)294.15K
L=1000ml
25.0g divided by 137.3g (formula mass of barium) = moles for barium
1 mole of barium = 1 mole of H2
H2 moles times 62.3638 L*mmHg/K*mol (these cancel out to L) times 294.15K over 748mmHg
Divide your answer which should be in L to ml by multiplying it by 1000.
(25/137.3)(62.3638×294.15)/748=answer×1000
I got 4.47x10∧3 but depending on how your teacher calls each number significant change your sig figs to the lowest number. Should look pretty similar. Good luck!