Answer:
1387.2g of Al2O3
Explanation:
The number of moles of aluminum oxide required to give the actual yield is obtained from the given mass of aluminum produced by the reaction. The percentage yield is used to obtain the theoretical yield of the aluminum. The number of moles produced theoretically can be used to calculate the amount of aluminum oxide required in moles and when we multiply the value obtained by the molar mass of aluminum oxide, we obtain the mass of aluminum oxide required.
Answer:
C
Explanation:
A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.
A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.
Answer:
Making oxygen
Oxygen can be made from hydrogen peroxide, which decomposes slowly to form water and oxygen:
hydrogen peroxide → water + oxygen
2H2O2(aq) → 2H2O(l) + O2(g)
The rate of reaction can be increased using a catalyst, manganese(IV) oxide. When manganese(IV) oxide is added to hydrogen peroxide, bubbles of oxygen are given off.
Apparatus arranged to measure the volume of gas in a reaction. Reaction mixture is in a flask and gas travels out through a pipe in the top and down into a trough of water. It then bubbles up through a beehive shelf into an upturned glass jar filled with water. The gas collects at the top of the jar, forcing water out into the trough below.
To make oxygen in the laboratory, hydrogen peroxide is poured into a conical flask containing some manganese(IV) oxide. The gas produced is collected in an upside-down gas jar filled with water. As the oxygen collects in the top of the gas jar, it pushes the water out.
Instead of the gas jar and water bath, a gas syringe could be used to collect the oxygen.
The Great Pacific Garbage Patch is created by deep oceans. The Marine Debris is litter that ends up in oceans or other large bodies of water.
