Answer:
A is the answer. Chemical changes happen when atomic bonds are broken or created during chemical reactions. Hence, in this case, it involve changes to molecular structure.
- Change in states are physical changes.
- When salts are dissolved in water, you can use Distillation to separate them. Distillation is a physical change as well.
- Dissolving is just physical change.
Explanation:
The statement that is true of a chemical change among the statements given in the question is "It involves changes in the molecular structure". The correct option among all the options that are given in the question is the first option or option "A". I hope the answer has actually come to your help.
we are asked to multiply 5.4 mm by 6.02 mm
5.4 mm has 2 significant figures
6.02 mm has 3 significant figures
When multiplying these 2 numbers the answer should have the least number of significant figures
From the 2 numbers the least number of significant figures is 2 , therefore answer should be rounded off to 2 significant numbers
5.4 x 6.02 = 32.5 rounded off is 33
Answer is b. 33 m^2
Answer:
79.7%
Explanation:
Percent yield of reaction is defined as the ratio between theoretical yield of a reaction and actual yield obtained.
In the problem, theoretical yield are 6 moles of KNO₃ and actual yield are 4.78 moles. Thus, percent yield is:
4.78 mol / 6 mol × 100 =<em> 79.7%</em>
