Answer:
2 half lives.
Explanation:
Suppose there are 100g of parent isotope at the start.
After 1 half-life there will be 50g of parent and 50g of daughter isotope.
After another half life there is 25 g of parent and 75g of daughter isotope.
Answer:
2. Option B.
Explanation:
H₂SO₄ + Ba(OH)₂ → BaSO₄ + 2H₂O
You can count 2H in sulfuric acid and 2 H in the barium hyrdoxide, so the coefficient for water must be 2.
You will have 4 H on both sides of the reaction.
Try with the dissociations of each reactant
Sulfuric acid ⇒ H₂SO₄ → 2H⁺ + SO₄⁻²
Barium hydroxide ⇒ Ba(OH)₂ → Ba²⁺ + 2OH⁻
Sulfate anion bonds to barium cation to produce the salt, therefore the 2 protons will bond the 2 hydroxide in order to produce, 2 moles of H₂O
2H⁺ + 2OH⁻ → 2H₂O
The mole fraction of solute in a 3.87 m aqueous solution is 0.0697
<h3>
calculation</h3>
molality = moles of the solute/Kg of the solvent
3.87 m dissolve in 1 Kg of water= 1000g
find the moles of water= mass/molar mass
that is 1000 g/ 18 g/mol= 55.56 moles
mole of solute = 3.87 moles
mole fraction is = moles of solute/moles of solvent
that is 3.87/ 55.56 = 0.0697