Answer:
0.043 M
Explanation:
The reaction that takes place is:
- Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂O
First we <u>calculate how many HCl moles reacted</u>, using the <em>given concentration and volume required to reach the equivalence point</em>:
- 0.029 M HCl * 37.3 mL = 1.0817 mmol HCl = 1.0817 mmol H⁺
As 1 mol of H⁺ reacts with 1 mol of OH⁻, in the 25.0 mL of the Ca(OH)₂ sample there are 1.0817 mmoles of OH⁻.
With that in mind we can <u>calculate the hydroxide ion concentration in the original sample solution</u>, using <em>the calculated number of moles and given volume</em>:
- 1.0817 mmol OH⁻ / 25.0 mL = 0.043 M
The simple trick which one can consider in such problem where it is asked for positron emission is :
<span>When the atomic number goes DOWN by one and mass number remains unchanged, then a positron is emitted.
</span>
<span>a. </span>
<span>
Here the atomic number decreases by one.
Similarly, options b and d are eliminated.
Option c is also not the answer.
For c, Count the atomic number on left side and compare it with right side. You will see it is 9 on left and 8 on right. Atomic no. did go down by 1. But the atomic mass is changed as well.
</span>
The theoretical yield is 204.4 g while the percent yield is 2.57%.
<h3>What is theoretical yield?</h3>
Theoretical yield is the amount of product obtained based on the stoichiometry of the reaction.
S8(s) + 8 Na2SO3(aq) + 40 H2O(l) --->8 Na2S2O3·5 H2O(s)
Number of moles of sulfur = 3.25 g /8(32) = 0.013 moles
Number of moles of sodium sulfite = 13.1 g/126 g/mol = 0.103 moles
Since 1 moles of sulfur reacts with 8 moles of sodium sulfite
0.013 moles reacts with 0.013 moles × 8 moles /1 mole = 0.104 moles
There is not enough sodium sulfite hence it is the limiting reactant.
1 mole of sodium sulfite yields 8 moles of product
0.103 moles of sodium sulfite yields 0.103 moles × 8 moles /1 mole = 0.824 moles
Mass of product = 0.824 moles × 248 g/mol = 204.4 g
percent yield = 5.26 g /204.4 g × 100/1
= 2.57%
Learn more about percent yield: brainly.com/question/2506978
Answer:
16 °C
Explanation:
Step 1: Given data
- Provided heat (Q): 811.68 J
- Mass of the metal (m): 95 g
- Specific heat capacity of the metal (c): 0.534 J/g.°C
Step 2: Calculate the temperature change (ΔT) experienced by the metal
We will use the following expression.
Q = c × m × ΔT
ΔT = Q/c × m
ΔT = 811.68 J/(0.534 J/g.°C) × 95 g = 16 °C
32.063 u is the answer, add all the variables and divide
