Answer:
7.5×10²³ ions
Explanation:
Given data:
Mass of magnesium sulfate = 75.0 g
Number of ions = ?
Solution:
Number of moles of magnesium sulfate:
Number of moles = mass/molar mass
Number of moles = 75.0 g/ 120.36 g/mol
Number of moles = 0.623 mol
Magnesium sulfate formula: MgSO₄
Number of moles of ions in 1 mole of MgSO₄ = 2 mol (Mg²⁺ and SO₄²⁻)
Number of moles of ion in 0.623 moles of MgSO₄:
2 mole ×0.623 = 1.246 mol
Number of ions:
1 mole contain 6.022×10²³ ions
1.246 mol × 6.022×10²³ ions / 1mol
7.5×10²³ ions
<span>the water is the solvent, and the powder is the solute. This is also a solution altogether. </span>
Frequency of photon = is 6.85 X 10¹⁴ sec⁻¹
Energy of photon , E = hv
where h is Planck's constant, v is the frequency of photon
E = 6.63 × 10⁻³⁴ J.s x 6.85 X 10¹⁴ s⁻¹
E = 4.54 x 10⁻¹⁹ J
Therefore, the energy of a photon of green light is 4.54 x 10⁻¹⁹ J.
Answer: 12.0 milliliters of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn.
Explanation:
moles =
moles of zinc =
The balanced chemical equation is :
According to stoichiometry:
1 mole of zinc reacts with = 2 moles of HCl
Thus 0.0390 moles of zinc reacts with = 
moles of HCl
To calculate the volume for given molarity, we use the equation:
.....(1)
Molarity of 
solution = 6.50 M
Volume of solution = ?
Putting values in equation 1, we get:
Thus 12.0 ml of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn
Answer:
There are often not more than one or two independent variables tested in an experiment.
