Answer:
2.17
Explanation:
To calculate pH using the hygrogen ion concentration we must use the following formula:
- log (H+) = pH
All we have to do now is plug in our hygrogen ion concentration and put it in our calculator.
- log (6.8 × 10⁻³) = 2.17
Don't forget proper figures for pH!
Answer: 1.005919176541433
Explanation:
The mass of CH₄ that is consumed is 10.598 g.
<h3>What is enthalpy?</h3>
The enthalpy of a system is defined as the sum of the internal energy of a system and the energy that is produced due to its pressure and volume.
It is given by
H = U+PV
The following reaction takes place during the combustion of CH₄
![CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g)](https://tex.z-dn.net/?f=CH_4%28g%29%2B2O_2%28g%29%5Crightarrow%20CO_2%28g%29%2B2H_2O%28g%29)
Energy evolved during the combustion, E = 587.9 kJ
Enthalpy of combustion of methane, ∆H = 890.3 kJ
![No of moles of CH_4 =\frac{energy evolved}{enthalpy of combustion}](https://tex.z-dn.net/?f=No%20of%20moles%20of%20CH_4%20%3D%5Cfrac%7Benergy%20evolved%7D%7Benthalpy%20of%20combustion%7D)
= 587.9 /890
Mass of CH₄ that is consumed = no of moles × molar mass of CH₄
= 587.9 /890 × 16
= 10.598 g
The mass of CH₄ which is consumed is 10.598 g
Learn more about enthalpy:
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Energy is released when a chemical bond forms
Answer:
K2 = 9.701 x 10^-10
Explanation:
K1 = 4.0 x 10^-5
K2 = ?
T1 = -10.8 °C +273 = 262.2K
T2 = -16 °C + 273 = 257K
ΔHrxn = 120. kJ/mol = 120000 J/mol
The formular relating all these parameters is given as;
ln( K2 / K1) = −ΔHrxn / R * (1 / T2 − 1 / T1)
ln (K2 / 4.0 x 10^-5) = - 120000 / 8.314 (1 / 257 - 1 / 262.2)
ln (K2 / 4.0 x 10^-5) = 1.1138
ln K2 - ln4.0 x 10^-5 = 1.1138
ln K2 = 1.1138 + ln4.0 x 10^-5
ln K2 = 1.1138 - 10.1266
ln K2 = -9.0128
K2 = 9.701 x 10^-10