13.5g H2O = 13.5/(2+16) = 0.75 mol H2O
Since for every O2 you can form 2 H2O, 0.75/2 = 0.375 mol of O2 will be needed to form 0.75 mol of H2O.
Converting from moles to molecules:
0.375 mol * 6.022 * 10^23 = 2.26 * 10 ^23 molecules
It will cover up all oxygen from the fire. And sand has no natural flammability because it is simply a crushed up mineral, so it can not make the fire any bigger.
Answer: a) Partial pressure of argon is 0.673 atm.
b) Partial pressure of ethane is 0.427 atm.
Explanation:
According to the ideal gas equation:'
P = Pressure of the argon gas = ?
V= Volume of the gas = 1.00 L
T= Temperature of the gas = 25°C = 298 K (0°C = 273 K)
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas = 
Thus the partial pressure of argon is 0.673 atm.
b) According to Dalton's law, the total pressure is the sum of individual pressures.





Thus partial pressure of ethane is 0.427 atm.
Valence Electron is the outermost electrons, family(Alkali) 1 has 1 valence electrons and family(Alkaline) 2 has 2 valence electrons.
Hope this helps
Answer:
Refer to the period table. Use the atomic mass for calculation. Multiply the atomic mass with the number of atoms. For example, Al2(SO4)3. (27 × 2) + (32 x 3) + (16 x 12) = molecular mass