Answer is: 5.22·10²² atoms of Iodine.
m(CaI₂) = 12.75 g; mass of calcium iodide.
M(CaI₂) = 293.9 g/mol; molar mass of calcium iodide.
n(CaI₂) = m(CaI₂) ÷ M(CaI₂).
n(CaI₂) = 12.75 g ÷ 293.9 g/mol.
n(CaI₂) = 0.043 mol; amount of calcium iodide.
In one molecule of calcium iodide, there are two iodine atoms
n(I) = 2 · n(CaI₂).
n(I) = 0.086 mol; amount of iodine atoms.
Na = 6.022·10²³ 1/mol; Avogadro number.
N(I) = n(I) · Na.
N(I) = 0.086 mol · 6.022·10²³ 1/mol.
N(I) = 5.22·10²²; number of iodine atoms.
Answer: 127 (3.s.f)
Explanation:
Boyle's law states that Volume x pressure = constant
Therefore let's first find the constant: 45 x 1900 = 85500
Then lets plug 675 ml and 85500 into the equation above:
675 x C = 85500
C = 127 (3 s.f.)
Answer:
Many plants have thorns on their stems or leaves. What is the MOST likely explanation for the evolution of thorns?
A) Thorns help plants produce more food from photosynthesis.
B) Thorns are an example of a mutation that arises in the genetic code of plants.
C) Thorns help plants to conserve resources like water and soil nutrients that may be used by other organisms.
D) Thorns are an adaptation that some plants have evolved in order to discourage herbivores from eating the plant.
2)
Explanation:
Base is Ca(OH)2.
Acid is H3PO4.
First part of the salt comes from base,
second par comes from the acid.
Mass of PH3= 6.086 g
<h3>Further explanation</h3>
Given
6.0 L of H2
Required
mass of PH3
Solution
Reaction
P4 + 6H2 → 4PH3
Assumed at STP ( 1 mol gas=22.4 L)
Mol of H2 for 6 L :
= 6 : 22.4 L
= 0.268
From the equation, mol PH3 :
= 4/6 x moles H2
= 4/6 x 0.268
= 0.179
Mass PH3 :
= 0.179 x 33,99758 g/mol
= 6.086 g
