Number of moles = mass of Ni /molecular mass of Ni
mass of nickel = 86.4 g
molecular mass of nickel = 58.69
number of moles of Ni in 86.4 g
=86.4/58.69
=1.472 mol
(rounded to four significant figures instead of three because the first digit of the answer starts with a 1).
Answer:
1. The same pattern of phases repeats monthly
2. Waxing moon phases are visible between the new and full moon
6. A full moon appears toward the middle of a lunar month
Explanation:
Moon has eight phases which is used by the ancient people for the identification of date of the month. Phases of moon tells us about the starting, middle and end of the month. At the starting of the month, waxing crescent appears while at the middle of the month, the moon gains its full shape. Phases which occurs between new and full moon is known as waxing.
Answer:
0.161moles
Explanation:
Given parameters:
Mass of Fe = 18g
Oxygen gas is in excess
Unknown:
Number of moles of Fe₂O₃ produced = ?
Solution:
To start with, let us write a chemically balanced equation before proceeding to understand the nuances of this problem.
4Fe + 3O₂ → 2Fe₂O₃
In the equation above above, 4 mole of iron combined with 3 moles of oxygen gas to 2 moles of Fe₂O₃.
In solving this problem, we can identify that Fe is the limiting reactant since we have been told oxygen gas is in excess. The suggests that the extent to which the product is formed and the reaction proceeds hinges on the amount of Fe we have.
It is best to work from the given, or known reactant to the unknown
The known in this scenario is the mass of Fe. Let us find the number of moles of this specie;
Number of moles of Fe = 
Molar mass of Fe = 56g/mol
Number of moles = 
= 0.32mol
Using this known number of moles of Fe, we can relate it to that of the unknown amount of the product and obtain the number of moles.
4 moles of Fe produced 2 moles of Fe₂O₃
0.32 moles of Fe will produce 
= 0.161moles
Answer:
NH₃
M = n/V(L)
0.844 mol (Both numbers have 3 significant figures so the result has 3 significant figures as well)
Explanation:
Step 1: Given and required data
- Volume of solution (V): 375. mL
- Molar concentration of the solution (M): 2.25 M
- Chemical formula for ammonia: NH₃
Step 2: Calculate the moles (n) of ammonia (solute)
Molarity is equal to the moles of solute divided by the liters of solution.
M = n/V(L)
n = M × V(L)
n = 2.25 mol/L × 0.375 L = 0.844 mol (Both numbers have 3 significant figures so the result has 3 significant figures as well)
Answer:
mass is the amount of substance contained in matter while volume is the space occupied by matter
in other words , mass talks about how heavy a body is while volume deals with the space covered by a 3- dimensional body. note : A 2- dimensional body can't occupy volume
