Nuclear reactions involve a change in an atom's nucleus, usually producing a different element. Chemical reactions, on the other hand, involve only a rearrangement of electrons and do not involve changes in the nuclei.
<em>ok</em>
Answer:
500 calories
Explanation:
I think USA Test prep gives a formula to use on this question so try and use that. If that does not help there is good video on khan academy explaining how to do it.
Answer:
pH = 12.5
Explanation:
The reaction that takes place is
- 2OH⁻(aq) + Pb⁺²(aq) → Pb(OH)₂(s)
The OH⁻ species come from the metal hydroxide of the solution, and Pb(OH)₂ is the precipitate.
Now we <u>convert 3.81 grams of Pb(OH)₂ into moles</u>, using its <em>molar mass</em>:
- 3.81 g ÷ 241.12 g/mol = 0.0158 mol Pb(OH)₂
Now we <u>convert 0.0158 Pb(OH)₂ moles into OH⁻ moles</u>, using the <em>stoichiometric coefficients of the reaction</em>:
- 0.0158 mol Pb(OH)₂ * = 0.0316 mol OH⁻
With the given concentration (1 L), we <u>calculate [OH⁻]</u>:
- [OH⁻] = 0.0316 mol / 1 L = 0.0316 M
Then we <u>calculate the pOH</u> of the solution:
And finally we <u>calculate the pH</u>:
Answer:
Mass percent concentration: 25,2% m/m
Explanation:
The percentage mass by mass indicates the grams of solute in 100 grams of solution. We convert the ml of water into g from the density formula:
δ= m/v m=δx v= 1 g/ml x 115 ml= 115 g
115g solution-----29 g NaCl
100g solution----x=(100g solutionx29 g NaCl)/115g solution
x=25,2173913 g NaCl