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
Answer:
2 - Bromo - 2 - Methyl Propane
Explanation:
The structure of the compound is given in the attached image as;
The longest chain is; CH₃--C--CH₃ = 3 carbon atoms = Propane
It has two substituents on the middle carbon = CH₃ and Br = 2 - Bromo- and 2 - Methyl
The IUPAC name is given as; 2 - Bromo - 2 - Methyl Propane
The amount of Silicon left after 300 years is 75g
It is given that the initial amount of Si is 100 times decay is 300 years and the half-life of Silicon is 710 years.
The radioactive decay formula is given by,
A = A₀ x 2^(-t/h);
where;
A is the resulting amount after t time, Ao is the initial amt (t=0),t is the time of decay, and h is the half-life of the substance.
On substituting the values from the given we get,
A = 100x2^(-300/710)
A = 100 x 0.746112347
A = 74.6112347 grams left after 300 yrs
Therefore, the number of grams of silicon left after 300 years is 74.6112347g. This value could be rounded off to 75 grams as in the whole number
To know more about half-life, click below:
brainly.com/question/1160651
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