D.
Q= m·ΔT·C(specific heat)= n·M·ΔT·C=10,5mol·27 g/mol· 194,5(225-30,5)·0,9=49600J=49,6kJ.
Answer:
21 kJ
Step-by-step explanation:
The formula for the heat q is
q = mCΔT
<em>Data:
</em>
m = 200 g; C = 4.184 J·°C⁻¹g⁻¹
T₁ = 50. °C; T₂ = 25 °C
<em>Calculations:
</em>
ΔT = T₂ - T₁
ΔT = 25 – 50.
ΔT = -25 °C
q = 200 × 4.184 × (-25)
q = -21 000 J Convert to kilojoules
q = -21 kJ
The negative sign shows that energy is released, so the water has released 21 kJ of energy.
Answer:
22.4 g
Explanation:
We know we will need a balanced equation with molar masses, so let’s gather all the information in one place.
M_r: 2.016
4H₂O + 2NH₃ ⟶ 2NO₂ + 7H₂; Δ<em>H</em> = 216 kJ/mol NH₃
1. Calculate the <em>moles of NH₃
</em>
216 kJ ≡ 1 mol NH₃
Moles NH₃ = 685 × 1/216
Moles NH₃ = 3.171 mol NH₃
2. Calculate the <em>moles of H₂</em>
The molar ratio is 7 mol H₂:2 mol NH₃
Moles of H₂ = 3.171 × 7/2
Moles of H₂ = 11.10 mol H₂
3. Calculate the <em>mass of H₂</em>
Mass of H₂ = 11.10 × 2.016
Mass of H₂ = 22.4 g
Answer:
Explanation:
Given parameters:
Number of breathe per minute = 15times
Volume of air per breath = 0.5L
Percentage of oxygen in air = 21%
Solution
There are 24 hours in a day.
60minutes makes a hour in a day,
I will breathe:
15 times x 60 x 24 = 21600 times in a day
The volume of air I will take in per day:
A breathe = 0.5L of air
21600breathe = 0.5 x 21600 = 10800L of air
Volume of oxygen I will breathe per day:
x 10800 = 2268L of oxygen
Answer: Option (b) is the correct answer.
Explanation:
When there are more number of hydroxide ions in a solution then there will be high concentration of or hydroxide ions. As a result, more will be the strength of base in that particular solution.
A base is strong when it readily dissociate into its ions in the solution. When a base is strong, then it does not matter at what concentration it is dissolved in the solution because despite of its low concentration it will remain a strong base.
Thus, we can conclude that out of the given options, the statement even at low concentrations, a strong base is strong best relates the strength and concentration of a base.