Answer:
D
Explanation:
There are principally three states of matter. These are the solid, liquid and gaseous states. The gaseous state has the highest degree of disorderliness as gas particles can move randomly while the solid state has the highest level of compactness.
Hence, we need to be adequately fed with information as regards the phase change to know if entropy has decreased or increased.
A. is wrong
Evaporation is a change of state to the gaseous state meaning there is an increased entropy.
B. is wrong
Sublimation is a change of state which means a solid substance like iodine or naphthalene changes its state directly to the gaseous state. There is an increased entropy here too.
C is wrong
Melting of ice means going from ice block to liquid water. This is synonymous to going from the solid state to the liquid state which is an increased entropy
D is correct
Condensation involves going from the gaseous state to the liquid state. This means going from a less ordered state to a more ordered state. This is accompanied by an entropy decrease.
E is wrong
While there are some processes that increase entropy, we also have some process that decrease entropy.
2H2O2 decomposes into the products 2H2O + O2(g)
Answer:
26.74g
Explanation:
The equation of the reaction is;
SIO₂ + 3C --> SiC +2CO
From the balanced equation, the relationship between SiC and C is;
3 mol of C produces 1 mol of SiC
Converting mol to mass using; Mass = moles * Molar mass
Mass of SiC = 1 mol * 40.11 g/mol = 40.11g
This means;
3 mol of C produces 40.11g of SiC
2 mol of C produces xg of SiC
3 = 40.11
2 = x
x = 2 * 40.11 / 3 = 26.74g
Answer:
Mass = 88.12 g
Explanation:
Given data:
Mass of iron oxide = 126 g
Mass of iron formed = ?
Solution:
Chemical equation:
Fe₂O₃ + 3CO → 2Fe + 3CO₂
Number of moles of iron oxide:
Number of moles = mass/molar mass
Number of moles = 126 g/ 159.69 g/mol
Number of moles = 0.789 mol
Now we will compare the moles of iron with iron oxide.
Fe₂O₃ : Fe
1 : 2
0.789 : 2/1×0.789 = 1.578 mol
Mass of iron:
Mass = number of moles ×molar mass
Mass = 1.578 mol × 55.84 g/mol
Mass = 88.12 g
