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Mila [183]
3 years ago
12

What two elements are used to make a laser pen light?

Chemistry
1 answer:
irina1246 [14]3 years ago
6 0

Answer:

Helium and Neon

Explanation:

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Butane C4H10 (g),(Hf = –125.7), combusts in the presence of oxygen to form CO2 (g) (Delta.Hf = –393.5 kJ/mol), and H2O(g) (Delta
shusha [124]

Answer: The enthalpy of combustion, per mole, of butane is -2657.4 kJ

Explanation:

The balanced chemical reaction is,

2C_4H_{10}(g)+13O_2(g)\rightarrow 8CO_2(g)+10H_2O(g)

The expression for enthalpy change is,

\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactants}]

Putting the values we get :

\Delta H=[8\times H_f_{CO_2}+10\times H_f_{H_2O}]-[2\times H_f_{C_4H_{10}+13\times H_f_{O_2}}]

\Delta H=[(8\times -393.5)+(10\times -241.82)]-[(2\times -125.7)+(13\times 0)]

\Delta H=-5314.8kJ

2 moles of butane releases heat = 5314.8 kJ

1 mole of butane release heat = \frac{5314.8}{2}\times 1=2657.4kJ

Thus enthalpy of combustion per mole of butane is -2657.4 kJ

3 0
3 years ago
1. A solution is always a mixture (true or false)
lakkis [162]

Answer:

yes solution is always a mixture but not all mixtures are solution

Explanation:

A solution.is a homogeneous mixture of substance that have uniform composition throughout

And a mixture hVe twoo or more substances that are not chemically.combine

4 0
3 years ago
Hydrofluoric acid is what type of acid?
posledela

Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material PTFE (Teflon).

5 0
2 years ago
Aluminium +hydrochloride acid ________+_________​
REY [17]

Answer:

Aluminium Chloride + Hydrogen

Please vote for Brainliest and I hope this helps!

4 0
2 years ago
Magnesium and Iodine will combine to make a compound. 
anygoal [31]
Magnesium and I think its MG12 for the other part
5 0
3 years ago
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