When PbSO₄ is added it dissociates as follows
PbSO₄ --> Pb²⁺ + SO₄²⁻
molar solubility is the number of moles of solute that can be dissolved in 1 L of solution
if molar solubility of PbSO₄ is X, then molar solubility of Pb²⁺ is X and SO₄²⁻ is X
the formula for ksp is as follows
ksp - solubility product constant
ksp = [Pb²⁺][SO₄²⁻]
ksp = X * X
ksp = X²
ksp = 1.82 x 10⁻⁸
X² = 1.82 x 10⁻⁸
X = 1.35 x 10⁻⁴ M
molar solubility of PbSO₄ is 1.35 x 10⁻⁴ M
answer is b.
Answer:
Explanation:
We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.
Look up the molar masses for the individual elements.
- Sodium (Na): 22.9897693 g/mol
- Oxygen (O): 15.999 g/mol
Look back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.
- Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/mol
Set up a ratio using the molar mass.
Multiply by the given number of grams.
Flip the ratio so the grams of sodium oxide can cancel each other out.
The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.
The 4 in the thousandth place tells us to leave the 8.
There are <u>2.48 moles of sodium oxide</u> in 154 grams, so choice A is correct.
<span>The correct answer is option 4. It is the hydroxide ions that is produced by an Arrhenius base in water. According to Arrhenius, acid-base reactions are characterized by acids which forms hydronium ions in water and bases which dissociates in aqueous solution to form hydroxide ions. </span>
1. 4 electrons
2. Ernest Rutherford
3. Discovered the existence of a center of atom
4. 17 protons