Answer:
Mass = 547.02 × 10⁻²³g
Explanation:
Given data:
Number of atoms of Al = 122 atom
Mass in gram = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
122 atom/6.022 × 10²³ atoms × 1 mol
20.26× 10⁻²³ mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 20.26× 10⁻²³ mol × 27 g/mol
Mass = 547.02 × 10⁻²³g
Answer:
Explanation:
<u>1) Data:</u>
Base: NaOH
Vb = 15.00 ml = 15.00 / 1,000 liter
Mb = ?
Acid: H₂SO₄
Va = 17.88 ml = 17.88 / 1,000 liter
Ma = 0.1053
<u>2) Chemical reaction:</u>
The <em>titration</em> is an acid-base (neutralization) reaction to yield a salt and water:
- Acid + Base → Salt + Water
- H₂SO₄ (aq) + NaOH(aq) → Na₂SO₄ (aq) + H₂O (l)
<u>3) Balanced chemical equation:</u>
- H₂SO₄ (aq) + 2 NaOH(aq) → Na₂SO₄ (aq) + 2H₂O (l)
Placing coefficient 2 in front of NaOH and H₂O balances the equation
<u>4) Stoichiometric mole ratio:</u>
The coefficients of the balanced chemical equation show that 1 mole of H₂SO₄ react with 2 moles of NaOH. Hence, the mole ratio is:
- 1 mole H₂SO₄ : 2 mole NaOH
<u>5) Calculations:</u>
a) Molarity formula: M = n / V (in liter)
⇒ n = M × V
b) Nunber of moles of acid:
- nₐ = Ma × Va = 0.1053 (17.88 / 1,000)
c) Number of moles of base, nb:
- nb = Mb × Vb = Mb × (15.00 / 1,000)
d) At equivalence point number of moles of acid = number of moles of base
- 0.1053 × (17.88 / 1,000) = Mb × (15.00 / 1,000)
- Mb = 0.1053 × 17.88 / 15.00 = 0.1255 mole/liter = 0.1255 M
Answer:
The heat produced is -15,1kJ
Explanation:
For the reaction:
2SO₂+O₂ → 2SO₃
The enthalpy of reaction is:
ΔHr = 2ΔHf SO₃ - 2ΔHf SO₂
As ΔHf SO₃ = -395,7kJ and ΔHf SO₂ = -296,8kJ
<em>ΔHr = -197,8kJ</em>
Using n=PV/RT, the moles of reaction are:
= <em>0,153 moles of reaction</em>
As 2 moles of reaction produce -197,8kJ of heat, 0,153moles produce:
0,153mol×
= <em>-15,1kJ</em>
<em></em>
I hope it helps!
Answer:D - adding a catalyst
Explanation:
The standard atomic weight is the average mass of an element in atomic mass units ("amu"). Though individual atoms always have an integer number of atomic mass units, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element.
