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
The correct answer is 2.70 × 10² g or 270 g.
It is given, that the density of a metal is 9.80 g/ml.
Let the mass of a sample of metal be x.
The sample of metal is dropped in 28.9 ml of water, due to which the volume of the water increases to 56.4 ml.
In order to calculate the mass of a metal, there is a need to use the formula, mass = density * volume
Mass = (9.80 g/ml) (56.4 ml - 28.9 ml)
= (9.80 g/ml) (27.5 ml)
= 2.70 × 10² g or 270 g
Answer:
The reason that that elements in the same 'group' have similar chemical properties is because they have the same number of valence electrons. ... Iron when reacting in chemical reactions loses electrons from its 4s orbital instead of its d orbital
About 25 percent of energy in an organism is used by the animal that eats it .
Please, you have to apply the formula below:<span>Q=c∗m∗Δt</span>where Q is the energy lost, c is the specific heat of water, m is the mass of water involved, so m=3.75 *10^-1 Kg c=4,184 J/(Kg*°C) delta t=37.5 °C
Taking density of water as 1000kg/m3. Mass of water would be 0.375kg. So, heat lost would be<span>H=mCDeltaT</span>H=0.375*4184*37.5 = 58837.5J
