The energy release when dissolving 1 mol of NaOH in water is 445.1 kJ
the mass of NaOH to be dissolved is 32.0 g
The number of NaOH moles in 32.0 g - 32.0 g / 40 g/mol = 0.8 mol
the energy released whilst dissolving 1 mol of NaOH - 445.1 kJ
when dissolving 0.8 mol - the energy released is 445.1 kJ/mol x 0.8 mol
therefore heat released is - 356.08 kJ
answer is -356.08 kJ
Ok so 40 percent of 3000 grams which is 3 kg is 1200 grams
So you would need 1.2kg or 1200 grams to make a 40% solution
im not sure about this one but i think the field is spread out
Answer:
0.645 liters
Explanation:
THE QUESTION IS equivalent 0.645 Liters
Fireworks owe their colors to reactions of combustion of the metals present. When Mg and Al burn, they emit a white bright light, whereas iron emits a gold light. Besides metals, oxygen is necesary for the combustion. The decomposition reactions of barium nitrate and potassium chlorate provide this element. At the same time, barium can burn emitting a green light.
(a) Barium nitrate is a <em>salt</em> formed by the <em>cation</em> barium Ba²⁺ and the <em>anion</em> nitrate NO₃⁻. Its formula is Ba(NO₃)₂. Potassium chlorate is a <em>salt</em> formed by the <em>cation</em> potassium K⁺ and the <em>anion</em> chlorate ClO₃⁻. Its formula is KClO₃.
(b) The balanced equation for the decomposition of potassium chloride is:
2KClO₃(s) ⇄ 2KCl(s) + 3O₂(g)
(c) The balanced equation for the decomposition of barium nitrate is:
Ba(NO₃)₂(s) ⇄ BaO(s) + N₂(g) + 3O₂(g)
(d) The balanced equations of metals with oxygen to form metal oxides are:
- 2 Mg(s) + O₂(g) ⇄ 2 MgO(s)
- 4 Al(s) + 3 O₂(g) ⇄ 2 Al₂O₃(s)
- 4 Fe(s) + 3 O₂(g) ⇄ 2 Fe₂O₃(s)
