Answer:
- <em><u>The third chice: 0.0750 M Na₂SO₄</u></em>
Explanation:
Assume 100% ionization:
<em><u>1) 0.100 M solution K₂SO₄</u></em>
- K₂SO4 (aq) → 2K⁺ (aq) + SO₄²⁻ (aq)
- Mole ratios: 1 mol K₂SO4 : 2 mol K⁺ + 1 mol SO₄²⁻ (aq) : 3 mol ions. This is 1 : 3
- At constant volume, the mole ratios are equal to the concentration ratios (M).
- 1 M K₂SO₄: 3 M ions = 0.100 M K₂SO₄ / x ⇒ x = 0.300 M ions
This means, that you have to find which of the choices is a solution that contains the same 0.300 M ion concentration.
<u>2) 0.0800 M Na₂CO₃</u>
- Na₂CO₃ (aq) → 2 Na⁺ + CO₃⁻
- 1 M Na₂CO₃ / 3 M ions = 0.0800M / x ⇒ x = 0.0267 M ions
This is not equal to 0.300 M, so this solution would not contain the same total concentration as a 0.100 M solution of K₂SO₄, and is not the right answer.
<u>3) 0.100 M NaCl </u>
- 1 M NaCl / 2 M ions = 0.100 M NaCl / x ⇒ x = 0.200 M ions
This is not equal to 0.300 M ion, so not a correct option.
<u>4) 0.0750 M Na₃PO₄</u>
- 1 M Na₃PO₄ / 4 M ions = 0.0750 M Na₃PO₄ / x ⇒ x = 0.300 M ions
Hence, this ion concentration is equal to the ion concentration of a 0.100 M solution of K₂SO₄, and is the correct choice.
<u>5) 0.0500 M NaOH </u>
- 1 M NaOH / 2 mol ions = 0.0500 M NaOH / x ⇒ x = 0.100 M ions
Not equal to 0.300 M, so wrong choice.
Answer: 3.5 moles of hydrogen gas will be produced.
Explanation:
The balanced chemical equation is:
As HCl gets completely used up, 
is the limiting reagent.
According to stoichiometry :
6 moles of produces = 3 moles of 
Thus 7.0 moles of produces=
of
Thus 3.5 moles of hydrogen gas will be produced.
Explanation:
Relation between length of a curve and angle is as follows.
l = 
where, R = radius of curve
= angle in radians
Also, l = 
.......... (1)
If curve has a degree of curvature 
for standard length s, then
R = 
........... (2)
Now, substitute the value of R from equation (2) into equation (1) as follows.
l = 
If s = 30 m, then calculate the value of l as follows.
l =
= 
= 452 m
thus, we can conclude that the length of the curve is 452 m.
