To determine the number of formula units in a sample of a compound you need to divide the number of grams by the formula mass. The formula mass of NaCl is 23 g/mol + 35.5 g/mol = 58.5 g/mol, and the number of grams of the sample is 0.14 mg * 1 g/ 1000 mg = 0.00014 g. Then the answer is 0.00014 g / 58.5 g = 2.30 * 10^ -6, which rounded to two significant figures is 2.4 * 10^ -6. So<span> the answer is 2.4 * 10^-6 or 0.0000024</span>
Dissociation of Pb₃(PO₄)₂ is;
Pb₃(PO₄)₂(s) ⇆ 3Pb²⁺(aq) + 2PO₄³⁻(aq)
initial - -
change -X +3X +2X
Equilibrium 3X 2X
Ksp = [Pb²⁺(aq)]³ [PO₄³⁻(aq)]²
1.0 x 10⁻⁵⁴ = (3X)³ (2X)²
1.0 x 10⁻⁵⁴ = 108X⁵
X = 6.21 x 10⁻¹² M
Hence the molar solubility of Pb₃(PO₄)₂ is 6.21 x 10⁻¹² M.
Answer:
mass of HCl = 243.5426 grams
Explanation:
1- we will get the mass of the reacting gold:
volume of gold = length * width * height
volume of gold = 3.2 * 3.8 * 2.8 = 34.048 cm^3 = 34.048 ml<span>
density = mass / volume
Therefore:
mass = density * volume
mass of gold = </span>19.3 * 34.048 = 657.1264 grams
2- we will get the number of moles of the reacting gold:
number of moles = mass / molar mass
number of moles = 657.1264 / 196.96657
number of moles = 3.3362 moles
3- we will get the number of moles of the HCl:
First, we will balanced the given equation. The balanced equation will be as follows:
Au + 2HCl ......> AuCl2 + H2
This means that one mole of Au reacts with 2 moles of HCl.
Therefore 3.3362 moles will react with 2*3.3362 = 6.6724 moles of HCL
4- we will get the mass of the HCl:
From the periodic table:
molar mass of H = 1 gram
molar mass of Cl = 35.5 grams
Therefore:
molar mass of HCl = 1 + 35.5 = 36.5 grams/mole
number of moles = mass / molar mass
Therefore:
mass = number of moles * molar mass
mass of HCl = 6.6724 * 36.5
mass of HCl = 243.5426 grams
Hope this helps :)
Answer:
Explanation:
Driving a car (burning gas is a chemical change) and almost all the plastics we use are made by chemical reactions of different components.
Answer:
41.67 mol
Explanation:
1 Litre of water = 1000g
Mole = mass / molar mass
Mass of 1 L of water = 1000 g
Molar mass of water (H2O) :
(H = 1, O = 16)
H2O = (1 * 2) + 16 = (2 + 16) = 18g/mol
Amount of water consumed = (3/4) of 1 litre
= (3/4) * 1000g
= 750g
Therefore mass of water consumed = 750g
Mole = 750g / 18g/mol
Mole of water consumed = 41.6666
= 41.67 mol
