The balanced equation for the neutralisation reaction is as follows
2H₃PO₄ + 3Mg(OH)₂ --> Mg₃(PO₄)₂ + 6H₂O
stoichiometry of H₃PO₄ to H₂O is 2:6
number of H₃PO₄ moles reacted - 0.24 mol
if 2 mol of H₃PO₄ form 6 mol of H₂O
then 0.24 mol of H₃PO₄ forms - 6/2 x 0.24 = 0.72 mol of H₂O
therefore 0.72 mol of H₂O are formed
4 significant figures. Use a rule called the Atlantic-Pacific rule where if the period is absent (Atlantic), you would start counting the numbers from right to left. If the period is present (Pacific), then start counting the numbers from left to right. Since the period is present, start from 5 and there are 4 digits including 5.
Answer:
The density is 5 g/cm3
Explanation:
The density (δ) is the ratio between the mass and the volume of a compound:
δ=m/v= 10 g/2 cm3= 5 g/cm3
If a metal is less reactive than carbon, it can be extracted from its oxide by heating with carbon. The carbon displaces the metal from the compound, and removes the oxygen from the oxide. This leaves the metal.
Answer:
, zirconium-103.
Explanation:
In a nuclear reaction, both the mass number and atomic number will conserve.
Let 
represent the unknown particle.
The mass number of a particle is the number on the upper-left corner. The atomic number of a particle is the number on its lower-left corner under the mass number. For example, for the particle , 
is the mass number while 
while is the atomic number.
Sum of mass numbers on the left-hand side of the equation:
.
Note that there are three neutrons on the right-hand side of the equation. Sum of mass numbers on the right-hand side:
.
Mass number conserves. As a result,
.
Solve this equation for :
.
Among the five choices, the only particle with a mass number of 103 is . Make sure that atomic number also conserves.
