Answer:
C
Explanation:
Think of 'exo' as exit and 'thermic' as relating to thermal energy/ heat. Thus, an exothermic release thermal energy as the reaction proceeds.
In an exothermic reaction, the total energy of the products is lesser than that of the reactants and ΔH (change in energy) is less than zero.
When heat is absorbed as the reaction proceeds, the chemical reaction is an endothermic reaction.
PV = nRT —> n = PV/RT
P = 2.90 atm
V = 4.80 L
R = 0.08206 L atm / mol K
T = 62.0 + 273 = 335 K (make sure you convert from celsius to kelvin)
n = (2.90 • 4.80) / (0.08206 • 335) = 0.506 moles of gas
Answer: Cu is oxidized while Au is reduced. The oxidizing agent is Au while the reducing agent is Cu
A) 5Ca(OH)₂ + 3H₃PO₄ → Ca₅(PO₄)₃(OH) + 9H₂O
B) m=158 g; w=0.830; m{Ca(OH)₂}=123 g
n(H₃PO₄) = m(H₃PO₄)/M(H₃PO₄) = mw/M(H₃PO₄)
n(H₃PO₄) = 158g*0.830/(98.0g/mol) = 1.3382 mol
n{Ca(OH)₂}=m{Ca(OH)₂}/M{Ca(OH)₂}
n{Ca(OH)₂}=123g/(74.01g/mol)=1.6619 mol
Ca(OH)₂:H₃PO₄ = 5:3
1.6619:1.3382 = 5:4 the limiting reagent is a calcium hydroxide
m{Ca₅(PO₄)₃(OH)} = M{Ca₅(PO₄)₃(OH)}n{Ca(OH)₂}/5
m{Ca₅(PO₄)₃(OH)} = 502.3g/mol*1.6619/5=166.954 g*
*The statement of the problem is incorrect, surplus of a phosphoric acid reacts with a hydroxyapatite. The calculated quantity of a hydroxyapatite is not formed.
3Ca₅(PO₄)₃OH + H₃PO₄ = 5Ca₃(PO₄)₂ + 3H₂O
Hey there!
Lithium has 3 protons.
Assuming this is a neutral atom, that means it will also have 3 electrons.
Atomic mass is the sum of protons and neutrons. We have 7 total protons and neutrons, and 3 electrons.
7 + 3 = 10
The total number of subatomic particles is 10.
Hope this helps!