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.
Answer:
h2+O ---> H2O
reactants: H2 & O
products: H2O
Explanation:
The simple reaction that produces a water molecule from H2 and O would be the one written above, even though there are 2 hydrogen molecules, they will form an H2 molecule rather than 2 individual H molecules (almost never seen) the reactants would be your hydrogen and oxygen molecules individually before they bond to form a molecule of water (H2O) which is the product
Answer:
Choice A: Approximately joules.
Explanation:
Apply the famous mass-energy equivalence equation to find the energy that correspond to the kilograms of mass.
,
where
- stands for energy,
- stands for mass, and
- is the speed of light in vacuum.
The speed of light in vacuum is a constant. However, finding the right units for this value can simplify the calculations a lot. What should be the unit of ?
The mass given is in the appropriate SI unit:
Mass is in kilograms.
Thus, proceed with the speed of light in SI units. The SI unit for speed is meters per second. For the speed of light, .
Apply the mass-energy equivalence:
.
The unit of energy is not in joules. Don't be alerted. Consider the definition of a joule of energy. One joule is the work done on an object when a force of one newton acts on the object in the direction of the force through the distance of one meter. (English Wikipedia.)
.
However, a force of one newton is defined as the force required to accelerated an object with a mass of one kilogram (not gram) at a rate of one meter per second squared. (English Wikipedia.)
.
In other words, the mass defect here is also .
Answer: There are 576.46 number of grams present in 16.95 mol hydrogen peroxide .
Explanation:
Number of moles is defined as the mass of substance divided by its molar mass.
The molar mass of is 34.01 g/mol. Hence, mass of hydrogen peroxide present in 16.95 moles is calculated as follows.
Thus, we can conclude that there are 576.46 number of grams present in 16.95 mol hydrogen peroxide .