Answer:
5.0 × 10²⁴ molecules
Explanation:
Step 1: Write the balanced double displacement reaction
2 NaOH + CuSO₄ ⇒ Na₂SO₄ + Cu(OH)₂
Step 2: Calculate the moles corresponding to 5.0 × 10²⁴ molecules of Na₂SO₄
We will use Avogadro's number: there are 6.02 × 10²³ molecules in 1 mole of molecules.
5.0 × 10²⁴ molecule × 1 mol/6.02 × 10²³ molecule = 8.3 mol
Step 3: Calculate the moles of CuSO₄ required to produce 8.3 moles of Na₂SO₄
The molar ratio of CuSO₄ to Na₂SO₄ is 1:1. The moles of CuSO₄ required are 1/1 × 8.3 mol = 8.3 mol.
Step 4: Calculate the molecules corresponding to 8.3 moles of CuSO₄
We will use Avogadro's number.
8.3 mol × 6.02 × 10²³ molecule/1 mol = 5.0 × 10²⁴ molecule
Answer: 670K
Explanation:
Given that,
Original volume of gas V1 = 1.22 L
Original temperature T1 = 286 K
New volume V2 = 2.86 L
New temperature T2 = ?
Since volume and temperature are involved while pressure is constant, apply the formula for Charles law
V1/T1 = V2/T2
1.22 L/286 K = 2.86 L/ T2
Cross multiply
1.22 L x T2 = 286 K x 2.86 L
1.22T2 = 817.96
Divide both sides by 1.22
1.22T2/1.22 = 817.96/1.22
T2 = 670.459 K (Round to the nearest whole number as 670 K)
Thus, the temperature of the gas is 670 Kelvin
4Al(s) + 3O2(g) --> 2Al2O3(s) This is the balanced.
From the equation:
4 moles of Al required 3 moles of O2 to produce 2 moles of Al2O3
3 moles of O2 reacted with 4 moles of Al to produce 2 moles of Al2O3
1 mole of O2 reacted with 4/3 moles of Al to produce 2/3 moles of Al2O3 (Divide by 3)
4.5 moles of O2 reacted with (4/3 *4.5) moles of Al to produce (2/3*4.5) moles of Al2O3
4.5 moles of O2 reacted with 6moles of Al to produce 3moles of Al2O3
(3) is the answer. 6 mol of Al.
<u>Question:</u>
For the cell constructed from the hydrogen electrode and metal-insoluble salt electrode, B) calculate the mean activity coefficient for 0.124 b HCl solution if E=0.342 V at 298 K
<u>Answer:</u>
The mean activity coefficient for HCl solution is 0.78.
<u>Explanation:</u>
Activity coefficient is defined as the ratio of any chemical activity of any substance with its molar concentration. So in an electrochemical cell, we can write activity coefficient as γ. The equation for determining the mean activity coefficient is
As we know that 
= 0.22 V and E = 0.342 V, the equation will become
So, the mean activity coefficient is 0.78.
