Answer:
0.877 mol
Step-by-step explanation:
We can use the<em> Ideal Gas Law </em>to solve this problem.
pV = nRT Divide both sides by RT
n = (pV)/(RT)
Data:
p = 646 torr
V = 25.0 L
R = 0.082 06 L·atm·K⁻¹mol⁻¹
T = 22.0 °C
Calculations:
(a) <em>Convert the pressure to atmospheres
</em>
p = 646 torr × (1 atm/760 torr) = 0.8500 atm
(b) <em>Convert the temperature to kelvins
</em>
T = (22.0 + 273.15) K = 295.15 K
(c) <em>Calculate the number of moles
</em>
n = (0.8500 × 25.0)/(0.082 06 × 295.15)
= 0.877 mol
Answer:
Molarity = 0.95 mol/dm³
Explanation:
Given data:
Volume of H₂SO₄ = 15.8 cm³
Volume of NaOH = 20 cm³
Concentration of NaOH = 1.5 mol/dm³
Concentration of H₂SO₄ = ?
Solution:
Chemical equation:
NaOH + H₂SO₄ → Na₂SO₄ + H₂O
First of all we will calculate the number of moles of NaOH and for that we will convert the units first,
Volume = 20 cm³/1000 = 0.02 L
Concentration of NaOH = 1.5 mol/dm³
1 mol/dm³ = 1 mol/L
Concentration of NaOH = 1.5 mol/L
Number of moles of NaOH:
Molarity = number of moles / volume in L
1.5 M = number of moles / 0.02 L
Number of moles = 1.5 M ×0.02 L
Number of moles = 0.03 mol
Now we will compare the moles of NaOH and H₂SO₄
NaOH : H₂SO₄
2 : 1
0.03 : 1/2×0.03 = 0.015 mol
Concentration of H₂SO₄:
Volume of H₂SO₄:
15.8 cm³/1000 = 0.0158 L
Molarity = number of moles / volume in L
Molarity = 0.015 mol / 0.0158 L
Molarity = 0.95 mol/L
1 mol/L = 1 mol/dm³
Molarity = 0.95 mol/dm³
All you need to do is change 5% into a decimal which would be 5/100 = .05
then multiply the decimal by the total volume to get the amount of active ingredients in ml
.05 * 56ml = 2.8 ml of active ingredient.
Hope that helps!
Answer:
Effective nuclear charge and ionization energy decreased down in the column.
Explanation:
Along Group:
As we move from top to bottom in group the atomic size increases with increase of atomic number. The electron is added into the next shell hence the valance electrons farther away from the nucleus and hold of nucleus become weaker on the valance electrons. The addition of electrons also increase the shielding and protect the outer electrons from the hold of nucleus. Thus it becomes easier to remove the electron from an atom and less energy is required that's why ionization energy decreases from top to bottom and effective nuclear charge also decrease because of shielding effect.
Along period:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons and shielding remain constant due to addition of electron in same shell. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases.
Answer:
Cost
Explanation:
The cost of purchasing a solar system is high so it serves as a great disadvantage.
