Answer:
c 18.0ml
Explanation:
The average mass of one H2O molecule is 18.02 amu. The number of atoms is an exact number, the number of mole is an exact number; they do not affect the number of significant figures. The average mass of one mole of H2O is 18.02 grams. This is stated: the molar mass of water is 18.02 g/mol.
Answer:
403 mL
Explanation:
First, I will assume that the mole is 1, because you are not specifing this.
Now, with the innitial data, we need to get the pressure:
T = 65+273 = 338 K
V = 500 / 1000 = 0.5 L
Now if:
PV = nRT
Then:
P = nRT/V and V = nRT/P
Let's calculate the P:
P = 1 * 0.082 * 338 / 0.5 = 55.432 atm
The standard temperature is 0° C or 273 K so, the volume is:
V = 1 * 0.082 * 273 / 55.432
V = 0.40384 L or simply 403.84 mL
Answer:
pH = 12.65
Explanation:
From the given information:
number of moles =mass in gram / molar mass
number of moles of KOH = mass of KOH / molar mass of KOH
number of moles of KOH = 0.251 g / 56.1 g/mol = 0.004474 mol
For solution :
number of moles = Concentration × volume
concetration = number of moles/ volume
concetration = 0.004474 mol / 0.100 L
concetration = 0.04474 M
We know that 1 moles KOH result into 1 mole OH⁻ ions
Therefore, Molarity of OH⁻ = 0.04474 M
Now,
pOH = -log[OH⁻]
pOH = -log (0.04474) M
pOH = 1.35
Similarly,
pH + pOH = 14
pH = 14 - pOH
pH = 14 - 1.35
pH = 12.65
