Answer:
The temperature at which a substance changes from the liq- uid state to the solid state is called the freezing point. The freez- ing point of the liquid state of a substance is the same temperature as the melting point of the solid state. For example, solid water melts at 0°C and liquid water freezes at 0°C.
Explanation:
To indicate whether the elements is basic or acid by changing of colour.(advantage)
can give out bad gas which can cause suffocate to the people.(disadvantage).
Answer:
5
Explanation:
We can obtain the value of x by doing the following:
Mass of hydrated salt (CuSO4.xH2O) = 1.50g
Mass of anhydrous salt (CuSO4) = 0.96g
Mass of water molecule(xH2O) = 1.50 — 0.96 = 0.54g
Molar Mass of CuSO4.xH2O = 63.5 + 32 + (16x4) + x(2 +16) = 63.5 + 32 + 64 + 18x = 159.5 + 18x
Mass of water(xH2O) molecules in the hydrate salt is given by:
xH2O/CuSO4.xH2O = 0.54/1.5
18x/(159.5 + 18x) = 0.36
Cross multiply to express in linear form
18x = 0.36 (159.5 + 18x)
18x = 57.42 + 6.48x
Collect like terms
18x — 6.48x = 57.42
11.52x = 57.42
Divide both side by 11.52
x = 57.42/11.52
x = 5
Therefore, the unknown integer x is 5 and the formula for the hydrated salt is CuSO4.5H2O
Answer:
ΔH°rxn = 54.08 kJ
Explanation:
Let's consider the following equations.
a) ClO(g) + O₃(g) ⇄ Cl(g) + 2 O₂(g) ΔH°rxn = –29.90 kJ
b) 2 O₃(g) ⇄ 3 O₂(g) ΔH°rxn = 24.18 kJ
We have to determine the value of heat of reaction for the following reaction: Cl(g) + O₃(g) ⇄ ClO(g) + O₂(g)
According to Hess's law, the enthalpy change in a chemical reaction is the same whether the reaction takes place in one or in several steps. That means that we can find the enthalpy of a reaction by adding the corresponding steps and adding their enthalpies. According to Lavoisier-Laplace's law, if we reverse a reaction, we also have to reverse the sign of its enthalpy.
Let's reverse equation a) and add it to equation b).
-a) Cl(g) + 2 O₂(g) ⇄ ClO(g) + O₃(g) ΔH°rxn = 29.90 kJ
b) 2 O₃(g) ⇄ 3 O₂(g) ΔH°rxn = 24.18 kJ
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Cl(g) + 2 O₂(g) + 2 O₃(g) ⇄ ClO(g) + O₃(g) + 3 O₂(g)
Cl(g) + O₃(g) ⇄ ClO(g) +O₂(g)
ΔH°rxn = 29.90 kJ + 24.18 kJ = 54.08 kJ
Answer:
Fossil record
Explanation:
but first think about it befor you do so it could be wrong im not a computer
