What is the mass percentage of iodine (i2) in a solution containing 4.0×10−2 mol i2 in 130 g of ccl4? express your answer using two significant figures. % request answer part b seawater contains 8.2×10−3 g sr2+ per kilogram of water. what is the concentration of sr2+ measured in ppm? express your answer using two significant figures. ppm p p m request answer

A. 7.2%

B. 8.6 ppm

Explanation:

Part A

First let's calculate the mass of I₂, 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 gMass percentage I₂ = 10.152 / 140.152 * 100 = 7.2%

Part B

The concentration of Sr⁺² in ppm is calculated using the formula

mg Sr⁺² / L water

We're given the mass of Sr⁺² in grams, so now we convert it into mg:

8.2x10⁻³g * = 8.2 mg

Now to convert kg of water into L, we use the density of seawater (1050 kg/m³):

Converting density: 1050 *   = 1.05 kg/L

Volume of one kilogram of water = 1kgWater ÷ 1.05 kg/L = 0.95 L

Finally we calculate the concentration of Sr⁺²:

8.2 mg / 0.95 L = 8.6 ppm

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant. 

Bis the answerhope it !