Whenever any substance goes under chemical change so any of the reaction will happen either both or multiple compounds will combine to produce combination reaction either one compound will decompose itself into 2 or more compounds or elements and last one is replacement reaction the either reaction is not even going to combination nor decomposition, So when a reaction like that happens it must replacement reaction.
Now the question is what's the condition required for it, so basically a chemical reaction when takes place it depends upon several factor on the basis of which we conclude products. The factors are Temperature,catalyst,reagents, either what is the mechanism of reaction, stability of reactants and stability of products and alot more.
During reaction sometimes gas forms and sometimes not yea and well that also depends on the chemical reactivity and stability of product sometimes product found itself most stable releasing the gas evolving so it's been done itself and sometimes we add catalyst and adjust the reaction to extract that gas and get desirable product manually.
I wrote all i know if sorry if this is not what you're looking for :(
The reaction between hydrogen and oxygen to form water is given as:

The balanced reaction is:

According to the balanced reaction,
4 g of hydrogen (
) reacts with 32 g of oxygen (
).
So, oxygen reacted with 29.4 g of hydrogen is:

Hence, the mass of oxygen that is reacted with 29.4 g of hydrogen is 235.2 g.
Answer:
A = 1,13x10¹⁰
Ea = 16,7 kJ/mol
Explanation:
Using Arrhenius law:
ln k = -Ea/R × 1/T + ln(A)
You can graph ln rate constant in x vs 1/T in y to obtain slope: -Ea/R and intercept is ln(A).
Using the values you will obtain:
y = -2006,9 x +23,147
As R = 8,314472x10⁻³ kJ/molK:
-Ea/8,314472x10⁻³ kJ/molK = -2006,9 K⁻¹
<em>Ea = 16,7 kJ/mol</em>
Pre-exponential factor is:
ln A = 23,147
A = e^23,147
<em>A = 1,13x10¹⁰</em>
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I hope it helps!
Answer:
CaO + SO 3 → CaSO. 4
This is an acid-base reaction (neutralization): CaO is a base, SO 3 is an acid.