Answer: 27.27%
Mass percentage of carbon in carbon dioxide is 4412×100=27. 27%.
When NH3 is dissolved in water, it dissociates partially producing NH4+ ions and OH- ions. It has an equation:
NH3 + H2O → NH4+ + OH-
<span>We use the Kb expression to determine the [OH-] concentration,
</span>
<span>Kb = [NH4+] [OH-] /* [NH3] </span>
We can write NH4+ as OH- since they are of equal ratio.
<span>(1.76*10^-5) = [OH-]² / 0.188
</span><span>[OH-]² = 3.3088*10^-6 </span>
<span>[OH-] = 1.819*10^-3 </span>
We calculate for H+ concentration as follows:
<span>[H+] [OH-] = 10^-14 </span>
<span>[H+] = 10^-14 / [OH-] </span>
<span>[H+] = 10^-14 / (1.819*10^-3) </span>
<span>[H+] = 5.50*10^-12 </span>
<span>pH = -log [H+] </span>
<span>pH = -log (5.5*10^-12) </span>
<span>pH = 11.26</span>
Answer:
3.5 g
Explanation:
The density of water is 1 g/mL. The mass (m) corresponding to 20.0 mL is 20.0 g.
We can calculate the heat (Q) required to raise the temperature of 20.0 mL of water 1 °C (ΔT).
Q = c × m × ΔT = 1 cal/g.°C × 20.0 g × 1 °C = 20 cal
where,
c is the specific heat capacity of water
There are 160 calories in 28 g of Cheetos. The mass that releases 20 cal is:
20 cal × (28 g/160 cal) = 3.5 g
