This is the balanced eq
N2 + 3H2 -> 2NH3
first you need to find mole of N2 by using
mol = mass ÷ molar mass.
mol N2= 20g ÷ (14.01×2)g/mol
=0.7138mol
then look at the coefficient between H2 and NH3.
it is N2:NH3
1:2
0.7138:0.7138×2
0.7138:1.4276 moles
moles of NH3 = 1.4276 moles
Answer:- It is choice D. 
Explanations:- In general, a neutralization reaction is the reaction of an acid with base to form salt and water.
in first reaction the reaction is taking place between ammonia(a base) and hydrochloric acid(an acid) to form their salt(ammonium chloride). So, it is an acid-base neutralization reaction.
In second reaction, sodium hydroxide(a base) is reacting with acetic acid(an acid) to form their salt(sodium acetate) and water. So, it is an acid-base neutralization reaction.
In third reaction, Nitric acid is reacting with calcium hydroxide(a base) to form a salt(calcium nitrate) and water. So, it is an acid-base neutralization reaction.
In fourth reaction, sulfuruc acid is reacting a sodium chloride(a salt) to give a double replacement reaction. It is not an acid-base neutralization reaction as it's not taking place between an acid and base.
So, the correct choice is D. 
Answer: polar molecule.
Explanation:
The boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid. The boiling point is dependent on the type of forces present.
Iodine monochloride (ICl) is a polar molecule due to the difference in electronegativities of iodine and chlorine. Thus the molecules are bonded by strong dipole dipole forces. Thus a higher temperature is needed to generate enough vapor pressure.
Bromine
is a non polar molecule as there is no electronegativity difference between two bromine atoms. The molecules are bonded by weak vanderwaal forces and thus has low boiling point.
Answer:
The pressure occupied is 1, 8 atm.
Explanation:
We use the Boyle´s Mariotte ´s law: for a given mass of gas at constant temperature, the pressure and volume vary inversely proportionally: P1xV1= P2xV2. The unit of pressure is converted to mmHg in atm.
760 mmHg----1 atm
912 mmHg---x= (912 mmHg x 1 atm)/760 mmHg=1,2 atm
P1xV1= P2xV2
P2=P1xV1/V2= 1,2 atm x 12 L/ 8L= <em>1, 8 atm</em>