Answer:
The percentage (by mass) of KBr in the original mixture was 33.1%.
Explanation:
The mixture of KCl and KBr has a mass of 3.595g, thus the sum of the moles of KCl (<em>x</em>) multiplied by it molar mass (74.5g/mol) and the moles of KBr (<em>y</em>) multiplied by it molar mass (119g/mol) is the total mass of the mixture:
Also, after the conversion of KBr into KCl, the total mass of 3.129 g is only from KCl moles, hence
But the 0.042 moles came from the originals KCl and KBr moles, thus
Now it is possible to propose a system of equations:
Solving the system of equations,
0.010 moles of KBr multiplied it molar mass is
Therefore, the percentage (by mass) of KBr in the original mixture was:
%
Answer:
Final concentrations:
Cu²⁺ = 0
Al³⁺ = 3.13 mmol/L = 84.51 mg/L
Cu = 4.7 mmol/L = 300 mg/L
Al = 0.57 mmol/L = 15.49 mg/L
Explanation:
2Al (s) + 3Cu²⁺ (aq) → 2Al³⁺ (aq) + 3Cu (s)
Al: 27 g/mol ∴ 100 mg = 3.7 mmol
Cu: 63.5 g/mol ∴ 300 mg = 4.7 mmol
3 mol Cu²⁺ _______ 2 mol Al
4.7 mmol Cu²⁺ _____ x
x = 3.13 mmol Al
4.7 mmol of Cu²⁺ will be consumed.
3.13 mmol of Al will be consumed.
4.7 mmol of Cu will be produced.
3.13 mmol of Al³⁺ will be produced.
0.57 mmol of Al will remain.
Answer:
Mass = 11.78 g of P₄
Explanation:
The balance chemical equation is as follow:
6 Sr + P4 → 2 Sr₃P₂
Step 1: Calculate moles of Sr as;
Moles = Mass / M/Mass
Moles = 50.0 g / 87.62 g/mol
Moles = 0.570 moles
Step 2: Find moles of P₄ as;
According to equation,
6 moles of Sr reacted with = 1 mole of P₄
So,
0.570 moles of Sr will react with = X moles of P₄
Solving for X,
X = 1 mol × 0.570 mol / 6 mol
X = 0.0952 mol of P₄
Step 3: Calculate mass of P₄ as,
Mass = Moles × M.Mass
Mass = 0.0952 mol × 123.89 g/mol
Mass = 11.78 g of P₄
Answer:
Wt. Avg. Atomic Weight => 63.35457 amu
Explanation:
Given Isotopic %Abundance fractional Wt Avg
At. Mass (amu) abundance contribution
Cu-63 62.93 69.09 0.6909 43.4783
Cu-65 64.9278 20.0668 0.200668 20.0668
Wt Average of all isotopes = ∑Wt Avg Contributions
= 43.4783 amu + 20.0668 amu = 63.35457 amu
3.81 kpa is the condition which is not true at STP
According to IUPAC the standard temperature and pressure that is STP the temperature is 273.15 k or 0 degrees celsius . and the absolute temperature of 101.325 Kpa or 1 atm. In addition at STP the volume of ideal gas is 22.4
