Answer:
1) 0.009 61 g C; 2) 0.008 00 mol C
Step-by-step explanation:
You know that you will need a balanced equation with masses, moles, and molar masses, so gather all the information in one place.
M_r: 12.01 44.01
C + ½O₂ ⟶ CO₂
m/g: 0.352
1) <em>Mass of C
</em>
Convert grams of CO₂ to grams of C
44.01 g CO₂ = 12.01 g C
Mass of C = 0.352 g CO₂ × 12.01 g C/44.01 g CO₂
Mass of C = 0.009 61 g C
2) <em>Moles of C
</em>
Convert mass of C to moles of C.
1 mol C = 12.01 g C
Moles of C = 0.00961 g C × (1 mol C/12.01 g C)
Moles of C = 0.008 00 mol C
All the carbon comes from Compound A, so there are 0.008 00 mol C in Compound A.
Calcium ions have oxidation state 2+ => Ca (2+).
Bromime ions (bromide) have oxidation state 1- => Br (-).
So, to be neutral the compound has to have two Br (-) ions per each Ca(2+) ion.
That is represented in the chemical formula as Ca Br2, where the number 2 to the right of Br is a subscript meaning that there are two atoms of Br per each atom of Ca (the lack of subscript means 1 atom).
Answer: Ca Br2.
Answer is: a line containin 7,7e15 cm.
gr(Cu) = 128 pm = 128e-12 m · 10² cm/1 m = 1,28e-8 cm.
n(Cu) = 1 mol.
Na = 6,022e23 1/mol; Avogadro number.
N(Cu) = n(Cu) · Na.
N(Cu) = 1 mol · 6,022e23 1/mol.
N(Cu) = 6,022e23.
l = r(Cu) · N(Cu).
l = 1,28e-8 cm · 6,022e23.
l = 7,7e15 cm.
Answer:
2.5 × 10⁻⁵ M H₃O⁺ and 4.0 × 10⁻¹⁰ M OH⁻.
Explanation:
∵ pH = - log[H₃O⁺]
∴ 4.6 = - log[H₃O⁺].
∴ log[H₃O⁺] = - 4.6.
<em>∴ [H₃O⁺] = 2.51 x 10⁻⁵.</em>
<em></em>
∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.
[H₃O⁺] = 2.51 x 10⁻⁵ M.
<em>∴ [OH⁻] = 10⁻¹⁴/[H₃O⁺] </em>= 10⁻¹⁴/(2.51 x 10⁻⁵ M) = <em>3.98 × 10⁻¹⁰ M ≅ 4.0 × 10⁻¹⁰ M.</em>
<em>So, the right choice is: 2.5 × 10⁻⁵ M H₃O⁺ and 4.0 × 10⁻¹⁰ M OH⁻.</em>
The air is so dry that when it hits a snowpack, the frozen water evaporates, going directly from the ice to vapor and bypassing the liquid phase entirely. This is called sublimation, and it's a common way for snow to disappear in the arid West."
