Answer:
The black circle represents C (Carbon) and the white circle represents O (Oxygen)
Explanation:
Answer:
there are 7. 505 x 1022 atoms in 3.5 grams of silicon.
Explanation:
So, 1 mole of silicon will have a mass of 28.0855 g and the number of atoms will be 6.022 x 1023. Therefore, there are 7. 505 x 1022 atoms in 3.5 grams of silicon.
For a proton, the charge is represented by +e
For an electron, the charge is represented by -e
The charge of an electron [e] is equal to the - 1.602 * 10^-19 Coulombs
For an ionized atom, the net charge is equal to the sum of charges in the proton and the electron in that atom.
From the question, we are told that, the iron atom has 26 protons and 7 electrons.
The net charge Q = 26 [ +e] + 7 [- e] = +19 e
+19 e = + 19 [1.602 * 10^-19 C] = + 3.04 * 10^-18 C.
Answer:
0.7561 g.
Explanation:
- The hydrogen than can be prepared from Al according to the balanced equation:
<em>2Al + 6HCl → 2AlCl₃ + 3H₂,</em>
It is clear that 2.0 moles of Al react with 6.0 mole of HCl to produce 2.0 moles of AlCl₃ and 3.0 mole of H₂.
- Firstly, we need to calculate the no. of moles of (6.8 g) of Al:
no. of moles of Al = mass/atomic mass = (6.8 g)/(26.98 g/mol) = 0.252 mol.
<em>Using cross multiplication:</em>
2.0 mol of Al produce → 3.0 mol of H₂, from stichiometry.
0.252 mol of Al need to react → ??? mol of H₂.
∴ the no. of moles of H₂ that can be prepared from 6.80 g of aluminum = (3.0 mol)(0.252 mol)/(2.0 mol) = 0.3781 mol.
- Now, we can get the mass of H₂ that can be prepared from 6.80 g of aluminum:
mass of H₂ = (no. of moles)(molar mass) = (0.3781 mol)(2.0 g/mol) = 0.7561 g.