If the item or substance has changed into a state where you are able to change it back such as:
Water melting
Water freezing
The test for this is fairly simple.
We take a glowing match or splint near the gas sample, if the glow intensifies, oxygen is present.
If a lit splint or match goes out with a popping sound, this means that hydrogen is present.
Answer:
Explanation:
You realize that C2H5OH releases -1277.3kJ/mol. We need to convert this to the amount based on the question. We that 22.52g of C2H5OH = 0.48884 mol.
This means that it will release (-1277.3)(0.48884) = 624.40 KJ of heat will be released. Note the negative sign is not necessary here (I think) because it says how much is released and not the change in heat of the system so it should be positive.
Answer:
Mass = 255 g
Explanation:
Given data:
Number of moles of nitrogen = 7.5 mol
Mass of ammonia formed = ?
Solution:
Chemical equation:
3H₂ + N₂ → 2NH₃
Now we will compare the moles of nitrogen and ammonia.
N₂ : NH₃
1 : 2
7.5 : 2/1×7.5 = 15
Mass of ammonia:
Mass = number of moles × molar mass
Mass = 15 mol × 17 g/mol
Mass = 255 g
Answer:
It is made up of two elements.
Explanation:
To answer the question given above,
We shall determine the number of elements present in CaCl₂. This can be obtained as follow:
CaCl₂ contains calcium (Ca) and chlorine gas (Cl₂).
This implies that CaCl₂ contains two different elements.
Now, considering the options given in the question above, CaCl₂ is made up of two elements.
