The volume in liters occupied by 22.6 g of I₂ gas at STP is 1.99 L (answer A)
<u><em>calculation</em></u>
Step: find the moles of I₂
moles= mass÷ molar mass
from periodic table the molar mass of I₂ is 253.8 g/mol
moles = 22.6 g÷253.8 g/mol =0.089 moles
Step 2:find the volume of I₂ at STP
At STP 1 moles =22.4 L
0.089 moles= ? L
<em>by cross multiplication</em>
={ (0.089 moles x 22.4 L) /1 mole} = 1.99 L
Answer:
- A) pH = 2.42
- B) pH = 12.00
Explanation:
<em>The dissolution of HCl is HCl → H⁺ + Cl⁻</em>
- To solve part A) we need to calculate the concentration of H⁺, to do that we need the moles of H⁺ and the volume.
The problem gives us V=2.5 L, and the moles can be calculated using the molecular weight of HCl, 36.46 g/mol:
= 9.60*10⁻³ mol H⁺
So the concentration of H⁺ is
[H⁺] = 9.60*10⁻³ mol / 2.5 L = 3.84 * 10⁻³ M
pH = -log [H⁺] = -log (3.84 * 10⁻³) = 2.42
- <em>The dissolution of NaOH is NaOH → Na⁺ + OH⁻</em>
- Now we calculate [OH⁻], we already know that V = 2.0 L, and a similar process is used to calculate the moles of OH⁻, keeping in mind the molecular weight of NaOH, 40 g/mol:
= 0.02 mol OH⁻
[OH⁻] = 0.02 mol / 2.0 L = 0.01
pOH = -log [OH⁻] = -log (0.01) = 2.00
With the pOH, we can calculate the pH:
pH + pOH = 14.00
pH + 2.00 = 14.00
pH = 12.00
Answer:
d. 117 grams
Explanation:
The mass of the table salt produced will be 117 grams.
Chemical reactions obey the law of conservation of mass. In this regard, matter is neither created nor destroyed in the course of a chemical reaction. It is expected that the mass of the reactants and products remain the same.
The reaction expression:
2Na + Cl₂ → 2NaCl
So, mass of sodium = 46g
mass of chlorine formed = 71g
Mass of NaCl = 46 + 71 = 117g
In general, if the temperature of a chemical reaction is increased, the reaction rate increases as well. The correct answer is A.