Answer:
Mass of aluminium in sample = 3.591 g ≅ 3.6 grams
Explanation:
Given that, A sample of aluminum absorbs 50.1 J of heat, upon which the temperature of the sample increases from 20.0°C to 35.5°C.
the specific heat of aluminum is 0.900 J/g- °C
The relation between heat absorbed and change in temperature is given by, Q = msΔT.
where Q = heat absorbed
m = mass of the substance
s = specific heat of substance
ΔT = change in temperature
Now, in our case, Q = 50.1 J ; s = 0.900 J/g- °C; ΔT= 35.5-20 = 15.5°C
⇒ m = 
⇒ m =
= 3.591 g ≅ 3.6 g
⇒ m ≅ 3.6 g
The empirical formula is the lowest reduced ration of the atoms present. In this case, it is P2O5
Answer:
1) [OH⁻] = 0.065 M
2) [H₃O⁺] = 1.54 x 10⁻¹³ M.
3) pH = 12.81.
Explanation:
HCl is completely dissociated yo its ions in solution:
<em>KOH + H₂O → H₃O⁺ + K⁺ + OH⁻,
</em>
<em></em>
1) [OH⁻] = 0.065 M.
<em>2) [H₃O⁺]:
</em>
∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.
∴ [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(0.065 M) = 1.54 x 10⁻¹³ M.
<em>3) pH:
</em>
For strong acids like HCl:
pH = - log[H₃O⁺] = - log[1.54 x 10⁻¹³ M] = 12.81.