The heat of the reaction is an extensive property: it is proportional to the quantity of the quantity that reacts.
The change in enthalpy is a measured of the heat evolved of absorbed.
When the heat is released, the change in enthalpy is negative.
The reaction of 2 moles of Na develops 368.4 kj of energy.
Calculate the number of moles of Na in 1.90 g to find the heat released when this quantity reacts.
Atomic mass of Na: 23 g/mol
#mol Na = 1.90 g / 23 g/mol = 0.0826 mol
Do the ratios: [368.4 kj/2mol ] * 0.0826 mol = 15.21 kj.
Then the answer is that 15.21 kj of heat is released (evolved)
Answer:
Here's what I get
Explanation:
SiO₂ + 4HF ⟶ SiF₄ + 2H₂O
The molar ratios are the same as the coefficients in the balanced equation.
Some of the molar ratios are
SiO₂:HF = 1:4
SiO₂:SiF₄ = 1:1
SiO₂:H₂O = 1:2
HF:SiF₄ = 4:1
HF:H₂O = 4:2
SiF₄:H₂O = 1:2
Answer:
Explanation:
<em>Percent ionization</em> is the percent of the original acid that has ionized:
- %, ionization = (molar concentration of hydrogen ions at equilibrium / molar concentration of original acid) × 100
<u><em>Part A:</em></u>
<u>1) Data:</u>
- Ka: 6.7 × 10 ⁻⁷
- [HA] = 0.10 M
- %, ionization = ?
<u>2) Equilibrium equation:</u>
<u>3) ICE (initial, change, equilbirium) table </u>
Concentrations
HA H⁺ A⁻
Initial 0.10 0 0
Change - x + x + x
Equilibrium 0.10 - x x x
- Equation: Ka = [H⁺] [A⁻] / [HA] =
6.7 × 10 ⁻⁷ = x² / (0.10 - x)
<u>4) Solve the equation:</u>
Since Ka << 1, you can assume x << 0.10 and 0.10 - x ≈ 0.10
- 6.7 × 10 ⁻⁷ ≈ x² / 0.10 ⇒ x² ≈ 6.7 × 10⁻⁸ ⇒ x ≈ 2.588 × 10⁻⁴
- % ionization ≈ (2.588 × 10⁻⁴ M / 0.1 M) × 100 ≈ 0.2588 % ≈ 0.26% (two significant figures)
<u><em>Part B:</em></u>
<u>1) Data:</u>
- Ka: 6.7 × 10 ⁻⁷
- [HA] = 0.010 M
- %, ionization = ?
<u>2) Equilibrium equation:</u>
<u>3) ICE table:</u>
Concentrations
HA H⁺ A⁻
Initial 0.010 0 0
Change - x + x + x
Equilibrium 0.010 - x x x
- Equation: Ka = [H⁺] [A⁻] / [HA] =
6.7 × 10 ⁻⁷ = x² / (0.010 - x)
<u>4) Solve the equation</u>:
Since Ka << 1, you can assume x << 0.010 and 0.010 - x ≈ 0.010
- 6.7 × 10 ⁻⁷ ≈ x² / 0.010 ⇒ x² ≈ 6.7 × 10⁻⁹ ⇒ x ≈ 8.185 × 10⁻5
- % ionization ≈ (8.185 × 10⁻⁵ M / 0.010 M) × 100 ≈ 0.8185 % ≈ 0.82% (two significant figures)
To sterilize the said baby bottle we have to raise the temperature from 22.0 degrees Celsius to 65 degrees Celsius and in order to determine the amount of heat that has to be supplied, we need the heat that would be absorbed by the baby bottle. First, we need to know the material of that baby bottle which, for this case, is made up of glass since we need the specific heat capacity of the material wherein for glass it is equal to 0<span>.84 J / g C. We determine the heat as follows:
Heat absorbed = Heat to be supplied = Heat transferred m C (T2 - T1)
Heat transferred = 50.0 g (0.84 J/ g C) (95 C - 22 C) = 3066 J</span>
The electromagnetic force is responsible for the electrostatic attraction and repulsion between charged particles and since the protons have positive charge and electrons have negative charge so the electromagnetic force will be the fundamental force primarily responsible for the attraction between electrons and protons