The answer is 10.4 because the unknown metal has displaced 27ml of water!
density= mass/volume
so therefore 280.8g/27ml= 10.4g/ml
Answer:
D) 2.01 x 10⁻⁴ .
Explanation:
pH = 2.11
[ H⁺ ] =
Let the acid be HA
It will ionise as follows .
HA ⇄ H⁺ + A⁻
in equilibrium .30
Acid ionisation constant Ka =
= 2 x 10⁻⁴
Mass of 1.5 mole of electron is 0.8229 mg
mass of electron = 9.11 * 10^-31 kg
mass of 1 mole of any substance ( Avagadro number ) = 6.022 * 10^23 /mol
1.5 moles of electron = 1.5 * 6.022 * 10^23 = 9.033 * 10^23 /mol
mass of 1.5 mole of electron = 9.033 * 10^23 * 9.11 * 10^-31
mass of 1.5 mole of electron = 8.229 * 10^-7 kg
mass of 1.5 mole of electron = 8.229 * 10^-4 g
mass of 1.5 mole of electron = 0.8229 mg
Hope it helps.....
This is the answer for the question above:
In order to solve this, first use stoichiometry for the energy in kJ released by, converting grams of CuO2 to moles:
<span>56.96g*(1 mole/143.09 g)=0.41904 moles of Cu2O </span>
<span>2 moles of Cu2O=-292.0kJ Convert 0.41904 moles of Cu2O to kJ. </span>
<span>Finally, solve for kJ: </span>
<span>0.41904 moles of Cu2O*(-292.0kJ/2 moles of Cu2O)=-61.18 kJ of energy released</span>