18 B 19 C and 20 A
cuz that's it I hope it helps you
Answer:
d = 14.9 g/mL
Explanation:
Given data:
Mass of metal = 22.4 g
Volume of eater = 3.2 mL
Volume of water + metal = 4.7 mL
Density of metal = ?
Solution:
Volume of metal:
Volume of metal = volume of water+ metal - volume of water
Volume of metal = 4.7 mL - 3.2 mL
Volume of metal = 1.5 mL
Density of metal:
d = m/v
d = 22.4 g/ 1.5 mL
d = 14.9 g/mL
<span>Clouds are made of tiny drops of water or ice crystals that settle on dust particles in the atmosphere. The droplets are so small - a diameter of about a hundredth of a millimetre - that each cubic metre of air will contain 100 million<span>droplets</span></span>
Answer: 12.0 milliliters of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn.
Explanation:
moles =
moles of zinc =
The balanced chemical equation is :
According to stoichiometry:
1 mole of zinc reacts with = 2 moles of HCl
Thus 0.0390 moles of zinc reacts with = 
moles of HCl
To calculate the volume for given molarity, we use the equation:
.....(1)
Molarity of 
solution = 6.50 M
Volume of solution = ?
Putting values in equation 1, we get:
Thus 12.0 ml of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn
The Solar System[b] is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly.[c] Of the objects that orbit the Sun directly, the largest are the eight planets,[d] with the remainder being smaller objects, the dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly—the natural satellites—two are larger than the smallest planet, Mercury.[e]
