Answer:
Mass = 240 g
Explanation:
Given data:
Number of molecules of NaOH = 3.618 × 10²⁴ molecules
Mass in grams = ?
Solution:
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.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For NaOH:
1 mole = 6.022 × 10²³ molecules
3.618 × 10²⁴ molecules × 1 mol / 6.022 × 10²³ molecules
0.6 × 10¹ moles
6 moles
Mass of NaOH:
Mass = Number of moles × molar mass
Mass = 6 mol × 40 g/mol
Mass = 240 g
Balancing the reaction is done to obey the law of nature, particularly, the Law of Definite Proportions. The concept is, the amount of the same element before and after the reaction must be the same. This is actually a redox reaction.
Oxidation half-reaction: Zn + 4 OH⁻ → Zn(OH)₄²⁻ + 2 e-
Reduction half-reaction: NO₃⁻ + 6 H₂O + 8 e-→ NH₃ + 9 OH⁻
Adding both reaction, we get the overall complete balanced equation:
<span>4Zn + NO</span>₃⁻ + 6 H₂O + 7 OH⁻ → 4 Zn(OH)₄²⁻ + NH₃
Thus, the charge in the product side is 4*-2 = <em>-8</em>.
For ideal gases at constant volume, you can use the law of Gay - Lussac:
P / T = constant => P1 / T1 = P2 / T2
=> P2 = T2 * P1 / T1
And remember you have to use absolute scale of temperature.
T1 = 25 + 273.15 = 298.15 K
T2 = 475 + 273.15 = 748.15 K
=> P2 = 748.15 K * 1.8 atm / 298.15 K = 4.5 atm
Answer: 4.5 atm
