Answer: 996 mmHg
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number
of particles.
According to the ideal gas equation:

P = Pressure of the gas = ?
V= Volume of the gas = 25.5 L
T= Temperature of the gas = 13°C = (273+13) K = 286K
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas= 1.42
(760mmHg=1atm)
Thus pressure of this gas sample is 996 mm Hg.
Answer:
C. two atoms of oxygen.
Explanation:
Step 1: Data given
Silicon has 14 electrons
Silicon is part of Group IV, all the elements there have 4 valence electrons.
It can form a compound when 4 valence electrons bind with the 4 valence elctrons of silicon
A. four atoms of calcium.
Calcium has 2 valence elctrons. 4 atoms of calcium <u>cannot bind</u> on 1 atom of silicon since there are only 4 valence electrons.
B. one atom of chlorine.
1 atom of chlorine has 7 valence electrons. Chlorine can bind with an atom with 1 valence electron. Since silicon has 4 valence electrons, they will <u>not bind.</u>
Silicon can bind with 4 atoms of chlorine to form SiCl4
C. two atoms of oxygen.
Oxygen has 6 valence electrons, this means oxygen can bind with an element with 2 valence electrons.
Since silicon has 4 valence electrons, it <u>can bind</u> with 2 atoms of oxygen to form SiO2 (silicon dioxide).
D. three atoms of hydrogen.
Hydrogen has 1 valence electron. 1 hydrogen atom can bind with an element that has 7 valence electrons.
Three atoms of hydrogen can bind with an element that has 5 valence electrons.
Silicon <u>will not</u> bind with 3 atoms of hydrogen ( but can bind with 4 atoms of hydrogen)
Mass =?
moles of N2 = 4.25 x 103 mol
molar mass of N2 = (14)x2 = 28
An example can be perspiration or even rain.
Hope this helps.