Answer:
Explanation:
We want to convert from moles to grams, so we must use the molar mass.
<h3>1. Molar Mass</h3>
The molar mass is the mass of 1 mole of a substance. It is the same as the atomic masses on the Periodic Table, but the units are grams per mole (g/mol) instead of atomic mass units (amu).
We are given the compound PI₃ or phosphorus triiodide. Look up the molar masses of the individual elements.
- Phosphorus (P): 30.973762 g/mol
- Iodine (I): 126.9045 g/mol
Note that there is a subscript of 3 after the I in the formula. This means there are 3 moles of iodine in 1 mole of the compound PI₃. We should multiply iodine's molar mass by 3, then add phosphorus's molar mass.
- I₃: 126.9045 * 3=380.7135 g/mol
- PI₃: 30.973762 + 380.7135 = 411.687262 g/mol
<h3>2. Convert Moles to Grams</h3>
Use the molar mass as a ratio.
We want to convert 3.14 moles to grams, so we multiply by that value.
The units of moles of PI₃ cancel.
<h3>3. Round</h3>
The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we calculated, that is the tens place.
The 2 in the ones place tells us to leave the 9.
3.14 moles of phosphorous triiodide is approximately equal to <u>1290 grams of phosphorus triodide.</u>
Answer:
Final temperature attained by water = 34.6°C
Explanation:
The reaction of CaO and H₂O is an <em>exothermic reaction</em>. The equation of reaction is given below:
CaO + H₂O ----> Ca(OH)₂
The quantity of heat given off, ΔH°rxn = 64.8KJ/mol = 64800J/mol
Number of moles of CaO = mass/molar mass, where molar mass of Ca0 = 56g/mol, mass of CaO = 10.1g
Number of moles of CaO = 10.1g/56g/mol =0.179moles
Quantity of heat given off by 0.179 moles = 64800 *0.179 = 11599.2J/mol
Using the formula, <em>Quantity of heat, q = mass * specific heat capacity * temperature rise.</em>
mass of mixture = (10.1 + 157)g = 167.1g, Initial temperature = 18.0°C
Final temperature(T₂) - Initial temperature(T₁) = Temperature rise
11599.2J/mol = 167.1g * 4.18J/g·°C * ( T₂ - 18.0°C)
11599.2 = 698.478T₂ - 12572.604
11599.2 + 12572.604 = 698.478T₂
698.478T₂ = 24171.804
T₂ = 34.6°C
Therefore, final temperature attained by water = 34.6°C
<h2>Answer : Electromagnetic energy</h2><h3>Explanation :</h3>
The solar panel usually combines multiple photo voltaic cells. Electromagnetic energy is used to power a solar panel. As the electromagnetic energy or rather radiations from the sun reaches to Earth in the form of radiation which is then collected by these photo voltaic cells. As the term solar energy simply suggests that the energy is coming from the sun. Thus, electromagnetic energy coming from the sun was produced when electric charges inside the sun change their potential energy.
For metals (lithium) reactivity increases down a group and from right to left across a period. So lithium is not that reactive. I think ♀️
