Answer:
14.7838
Explanation:
Given that;
A student uses a solution that contains 16 g of water to conduct an experiment and at the end of an hour ; the amount have decreased by 3.5%
The mathematically illustration for this is given as
= 16 g × 3.5%
= 
= 0.56
After an hour; the amount have decreased by 16 - 0.56
= 15.44
after 2 hours the water decreased by another 4.25%
i.e 
⇒ 0.6562
after two hours , the amount would have decreased by:
= 15.44 - 0.6562
= 14.7838
Answer: 72 grams of
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number
of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of
requires 5 moles of oxygen
0.45 moles of
require=
moles of oxygen
Mass of 
72 grams of
are needed to completely burn 19.7 g 
Volume= Mass/ Density= 20/184
= 0.108 cubic cm
Answer:
6 hours
Explanation:
If it is traveling at 50mph and needs to reah 300 miles, to figure this problem out you would want to divide 300 by 50 to get 6 hours. So it will take six hours until the car travels 300 miles
Hope this helps.