A chemical change is characterized of the formation of new substances or a chemical reaction. There are a number of observations that we can see if this type of change happens. One would be the formation of gas bubbles, this indicates that one of the products is a gas. Another observation would be a formation of a precipitate in the solution, it would indicate that the new solid formed is not soluble in the solution. A permanent color change in the solution would also indicate a chemical change because it may be that the new substance that is formed has its own distinct color when in solution.
Here are the answers that would best complete the given statement above. The air you breathe is made of 21% oxygen and 78% nitrogen. The oxygen in air is the SOLUTE and the nitrogen is the SOLVENT. In a given mixture, the reagent having the highest percentage of amount is always the solvent and the one or ones having the lower percentages are the solutes. Hope this answer helps.
Answer:
The half-life of Material 1 and Material 2 are equal.
step by step explanation;
Material 1 disintegrates to half its mass three times in 21.6 s, to go from 100g
to 12.5g. That is,
100g - 50g - 25g - 12.5g
Material 2 disintegrates to half its mass three times in 21.6 s, to go from 200g to 25g. That is,
200g - 50g - 25g - 12.5g.
This means that regardless of their initial masses involved, material 1 and material 2 have equal half-life.
Their half-life is 21.6 ÷ 3 = 7.2 sec
