Answer:
A. 7.2%
B. 8.6 ppm
Explanation:
<em>Part A</em>
First let's <em>calculate the mass of I₂</em>, using the known value of moles and the molecular weight (253.8 g/mol)
- 4.0x10⁻² mol I₂ * 253.8 g/mol = 10.152 g I₂
Mass percentage is calculated using the mass of I₂ and the total mass (mass of I₂ + mass of CCl₄)
- Total mass = 130 + 10.152 = 140.152 g
- Mass percentage I₂ = 10.152 / 140.152 * 100 = 7.2%
<em>Part B</em>
The concentration of Sr⁺² in ppm is calculated using the formula
We're given the mass of Sr⁺² in grams, so now we <u>convert it into mg</u>:
- 8.2x10⁻³g *
= 8.2 mg
Now to convert kg of water into L, we use the density of seawater (1050 kg/m³):
<em>Converting density</em>: 1050 
* 
= 1.05 kg/L
- Volume of one kilogram of water = 1kgWater ÷ 1.05 kg/L = 0.95 L
Finally we<u> calculate the concentration of Sr⁺²</u>:
- 8.2 mg / 0.95 L = 8.6 ppm
Density = mass/volume
Density = 81g/0.9cm³
Density = 90g/cm³
: )
Answer:
A = 8
B = 8
C = O ( Oxygen )
D = 26
E = 30
F = Fe (Iron)
Explanation:
1)To get "A" we use the following formula
mass number = number of protons + number of. neutrons
15 = number of protons + 7
15 - 7 = number of protons
8 = number of protons
A = 8
2)To find "B"
atomic number = number of protons
Atomic number = 8
B = 8
3)To find "C"
the atomic number is 8 so the element which
has 8 atomic number on periodic table is Oxygen.
C = oxygen
4) To get "D"
Number of protons = atomic number
number of protons = 26
D = 26
5)To get "E"
mass number = number of protons + number of. neutrons
56 = 26 + number of neutrons
56 - 26 = number of neutrons
number of neutrons = 30
E = 30
6) To find "F"
The atomic number is 26 so the element which has 26 atomic number on periodic table is Iron.
hope it helps
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