In one H₂O molecule, there are two hydrogen atoms along with one oxygen atom. So for every 1 oxygen atom (of which there are 2 of in an oxygen gas molecule) there needs to be 2 hydrogen atoms per oxygen( which in the equation of 2H2 +O2–> 2H2, that 2 H2 is broken down into 4 hydrogen atoms which means 2 hydrogen atoms have to bond to 1 oxygen atom and with 4 hydrogen atoms, there will be 2 atoms of oxygen which creates 2 molecules of water.
So to solve the question,
10.5g/2=5.25g of oxygen required to fully react with hydrogen to make water
Answer:
period 3 and group 3
Explanation:
I'm saying group 3 because that is how I learnt it at school, but if you count it then it's in group 13.
Currently they have discovered 118
Answer:

Explanation:
Data provided as per the question below:-
Wavelength = 430.nm
The computation of the frequency of the light is shown below:-
Frequency = Velocity of light ÷ Wavelength
The Velocity of light = 
Wavelength = 430 nm =
m
Frequency = 


= 
Therefore for determining the frequency we simply applied the above formula.
Answer:
C
Explanation:
A fuel cell uses both hydrogen and oxygen as fuels. At the cathode oxygen is reduced to water according to the equation
O2+4H^+ +4e ------>2H2O
And hydrogen is oxidized at the anode:
2H2------>4H^+ +4e
Fuel cells produce only water as a by product hence they are environment friendly