The answer would be B, an electron because the proton is positive, neutron is neutral, and the nucleus is the center of the atom.
Answer:
pineal body is a vastigious structure which signifies same origin of chimpanzee and modern man
Explanation:
Answer:
Molecular formula naphthalene → C₁₀H₈
Empirical formula naphthalene → C₅H₄
Explanation:
Centesimal composition means that in 100 g of compound we have x g of the element. Therefore in 100 g of naphthalene we have:
93.7 g of C
6.3 g of H
Let's make a rule of three:
In 100 g of naphthalene we have 93.7 g of C and 6.3 g of H
In 128 g of naphthalene we would have:
128 . 93.7 / 100 = 120 g of C
128. 6.3 / 100 = 8 g of H
We convert the mass to moles, by molar mass:
120 g . 1mol / 12 g = 10 moles C
8 g . 1mol/ 1g = 8 moles H
Molecular formula naphthalene → C₁₀H₈
Empirical formula naphthalene → C₅H₄
(The sub-index of each element is divided by the largest possible number)
Answer:
1) 2Al + 6HCl ⟶ 2AlCl₃ + 3H₂
Fe + 2HCl ⟶ FeCl₂ + H₂
2) Cu = 2.5 g; Al = 3.5 g; Fe = 4.0 g
Explanation:
1) Possible reactions
2Al + 6HCl ⟶ 2AlCl₃ + 3H₂
Fe + 2HCl ⟶ FeCl₂ + H₂
2) Mass of each metal
a) Mass of Cu
The waste was the unreacted copper.
Mass of Cu = 2.5 g
b) Masses of Al and Fe
We have two relations
:
Mass of Al + mass of Fe = 10 g - 2.5 g = 7.5 g
H₂ from Al + H₂ from Fe = 6.38 L at NTP
i) Calculate the moles of H₂
NTP is 20 °C and 1 atm.

(ii) Solve the relationship
Let x = mass of Al. Then
7.5 - x = mass of Fe
Moles of Al = x/27
Moles of Fe = (7.5 - x)/56
Moles of H₂ from Al = (3/2) × Moles of Al = (3/2) × (x/27) = x
/18
Moles of H₂ from Fe = (1/1) × Moles of Fe = (7.5 - x)/56
∴ x/18 + (7.5 - x)/56 = 0.2652
56x + 18(7.5 - x) = 267.3
56x + 135 - 18x = 267.3
38x = 132.3
x = 3.5 g
Mass of Al = 3.5 g
Mass of Fe = 7.5 g - 3.5 g = 4.0 g
The masses of the metals are Cu = 2.5 g; Al = 3.5 g; Fe = 4.0 g