We are given that:
1 atom N = 3 atom of the metal
1 mol N = 3 mol of the metal
First let us convert the given nitrogen into number of
moles:
moles N = 1 g / (14 g / mol)
moles N = 0.071 mol
Therefore the atomic or molar mass of the metal is:
molar mass = 1.486 g / (3 * 0.071 mol)
<span>molar mass = 6.93 g / mol</span>
Answer:
4
10
Explanation:
The reaction equation is given as;
Ca(OH)₂ → Ca²⁺ + 2OH⁻
Concentration of Ca(OH)₂ = 5 x 10⁻⁵M
Unknown:
pOH of the solution = ?
pH of the solution = ?
Solution:
Solve for the pOH of this solution using the expression below obtained from the ionic product of water;
pOH = ⁻log₁₀[OH⁻]
Ca(OH)₂ → Ca²⁺ + 2OH⁻
1moldm⁻³ 1moldm⁻³ 2 x 1moldm⁻³
5 x 10⁻⁵moldm⁻³ 5 x 10⁻⁵moldm⁻³ 2( 5 x 10⁻⁵moldm⁻³ )
1 x 10⁻⁴moldm⁻³
Therefore;
pOH = -log₁₀ 1 x 10⁻⁴ = 4
Since
pOH + pH = 14
pH = 14 - 4 = 10
Answer:
18.1 g
Explanation:
You know that the atomic weight of phosphorus is equal to
30.794 u
, where
u
represent the unified atomic mass unit.
The unified atomic mass unit is equivalent to
1 g/mol
, but let's take the long road and prove that identity.
Now, the unified atomic mass unit is defined as
1
12
th
of the mass of a single unbound carbon-12 atom in its ground state and is equivalent to
1 u
=
1.660539
⋅
10
−
24
g
This means that the mass of one phosphorus atom will be
30.974
u
⋅
1.660539
⋅
10
−
24
g
1
u
=
5.14335
⋅
10
−
23
g
You know that one mole of any element contains exactly
6.022
⋅
10
23
atoms of that element - this is known as Avogadro's number.
Well, if you know the mass of one phosphorus atom, you can use Avogadro's nubmer to determine what the mass of one mole of phosphorus atoms
5.14335
⋅
10
−
23
g
atom
⋅
6.022
⋅
10
23
atoms
1 mole
=
30.974 g/mol
Finally, if one mole of phosphorus atoms has a mass of
30.974 g
, then
0.585
moles will have a mass of
0.585
moles
⋅
30.974 g
1
mole
=
18.1 g
From: https://socratic.org/questions/the-atomic-weight-of-phosphorus-is-30-974-u-what-is-the-mass-of-a-phosphorus-sam
Answer:
42.3moles
Explanation:
The chemical equation given in this question is as follows:
H2 + O2 → H2O
However, this equation is unbalanced, the balanced chemical equation is as follows:
2H2 + O2 → 2H2O
This equation shows that;
2 moles of hydrogen gas (H2) will produce 2 moles of water (H2O)
Hence, If 42.3 moles of water (H2O) are produced, 42.3 × 2/2
= 42.3moles of hydrogen was reacted.
