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: only Br2.
Justification.
In a chemical reaction the element that gains electrons experiments a reduction in its oxidation state, that is why it is said that it is reduced.
So, to know what element is being reduced you need to calculate the oxidation states of the elements involved.
Here I indicate the oxidation states of each element if the reaction putting them inside parenthesis:
Reactants side Products side
K (0) K (1+)
Br (0) Br(1-)
So, K lost one electron, increasing its oxidation statefrom 0 to 1+, meaning that it is being oxidized.
And, each atom of Br gained one electron, reducing its oxidation state from 0 to 1-, meaning it is being reduced.
Therefore, the answer is that Br2 is the substance being reduced.
<span>3) which is an example of a physical change
</span><span>a) grinding pepper</span>
Explanation:
What you call polyester is technically polyethylene terephthalate or PET plastic molded into filaments that are then woven into fabric. It's made in a chemical reaction between ethylene glycol and therephthalic acid, and these chemicals are derived from fossil fuels, air, and water.
Nylons are condensation polymers or copolymers, formed by reacting difunctional monomers containing equal parts of amine and carboxylic acid, so that amides are formed at both ends of each monomer in a process analogous to polypeptide biopolymers. Most nylons are made from the reaction of a dicarboxylic acid with a diamine or a lactam or amino acid with itself
The binder resin in acrylic paint is man-made, most of the time in some sort of lab. It is made generally from the monomer methyl methacrylate and also any real common catalyst. The catalyst speeds up the reaction to where the monomers create extremely long chains. Which result in polymethyl methacrylate, an acrylic plastic polymer.
The pigments are also mostly made in labs/factories. Most of the time they are either pure elements like pure cobalt powder and carbon charcoal, or they basic bounded compounds like cadmium sulfide. To make cadmium sulfide you react cadmium chloride with hydrogen sulfide to make a bright yellow solid. It is then washed and heated to make a spectrum of different colors.
Basically all of acrylic paints are man-made through various chemical reactions.
Answer:
Explanation: A square of dry ice has a surface temperature of - 109.3 degrees Fahrenheit (- 78.5 degrees C). Dry ice additionally has the extremely decent component of sublimation - as it separates, it transforms legitimately into carbon dioxide gas as opposed to a fluid.