Answer: because a mole is based on Avogrado's number, which is 6.02 x 10²³ particles. It isn't possible to directly count that many particles at a time.
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.
It is false, hope this helps!
12 times breathe give 240 ml of pure 
. Each breathe gives 20 ml of .
Let us consider, volume of air per breathe= x ml.
Pure from inhaled air= 
ml and Pure from exhaled air= 
ml.
Pure from inhaled and exhaled air= 20 ml
So, + = 20
Therefore, x = 55.5 ml
So, volume of air per breath= 55.5 ml.
Answer:
hey mate
Explanation:
Formula for Acceleration Due to Gravity
These two laws lead to the most useful form of the formula for calculating acceleration due to gravity: g = G*M/R^2, where g is the acceleration due to gravity, G is the universal gravitational constant, M is mass, and R is distance.
