Answer:
C) Chemical changes involve formation of a new substance while physical change only impacts appearance or form.
Explanation:
The obvious difference between a chemical change and physical change is that in a chemical change new substances are produced while in a physical change, the form of the compounds are altered.
- Most phase changes are products of physical changes. Such changes are easily reversible.
- In a chemical change, a new kind of matter is formed. It is accompanied by energy changes.
- The process is not easily reversible.
<u>Answer:</u> The gas produced when sodium phosphide reacts with water is phosphine.
<u>Explanation:</u>
When sodium phosphide reacts with water molecule, it leads to the production of flammable, poisonous gas known as phosphine along with the production of sodium hydroxide.
The chemical reaction for the reaction of sodium phosphide with water follows the equation:
By Stoichiometry of the reaction:
1 mole of sodium phosphide reacts with 3 moles of water to produce 1 mole of phosphine gas and 3 moles of sodium hydroxide.
Hence, the gas produced when sodium phosphide reacts with water is phosphine.
First we need to find the number of moles that 43.9g of gallium metal is. We can do this by finding the molar weight of gallium and cross-multiplying to cancel out units:
So we are dealing with 0.63 moles of gallium metal.
We can take from the balanced equation that 4 moles of gallium metal will react completely with 3 moles of oxygen gas. We can take this ratio and make a proportion to find the amount of oxygen gas, in moles, that will react completely with 0.63 moles of gallium metal:
Cross multiply and solve for x:
So now we know that 0.47 moles of oxygen gas will react with 43.9g of gallium metal.
Our coefficients would be:
C12H22O11: 1
O2: 12
CO2: 12
H2O: 11
Why?
With the coefficients, our reactants would be:
12 carbons, 22 hydrogens, and 35 oxygens.
To obey the law of conservation of mass, we would have to have an equal amount of each of those elements on the products side, since so much of that element needs to form an equal amount on the other side.
So, with those coefficiens, our products would be:
12 carbons total, 35 oxygens total, and 22 hydrogens total. If we compare to the reactants side, they are all equal!
And, since 1 or 11 cannot be simplifyed any smaller, we know the equation is completely balanced.
Hope I could help!
Answer: -
Fission creates large amounts of radioactive waste.
Explanation: -
During nuclear fission, by products are formed. These by products are radioactive in nature. They give radiation. These radiation causes a lot of harm to humans including cancer and mutations.
Thus, Fission creates large amounts of radioactive waste.
