<span>In the club Pathfinders the tesoreiro should get in shape?</span>
Answer:
Its C
Explanation:
Got 100% on test edge 2020
Polyethylene or Polythene is one of the most common plastics used all around the world. It is very widely produced, with around 80 million tonnes every single year!
It is used for the following
- Plastic bags
- Plastic films
- Geomembranes (low permeable sheets that act like a barrier or a line separating two substances to control fluids)
- Dustbin crates
- Water pipes
- Plastic bottles
- Packaging
Answer:
<em><u>Question 1.</u></em><em> → </em>The amount remained is 15.625 g after 5 half-lives (30 hours).
<u><em>Question 2. </em></u><em>→ </em>mass % of water =41.4 %
<u><em>Question 3. </em></u><em>→ </em>C. 64 grams.
Explanation:
<em><u>Question 1. </u></em>
It is known that the decay of isotopes and radioactive material obeys first order kinetics.
Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
Thus, 30 hours represent (30/6) 5 half-lives.
500 g →(first 1/2 life) 250 g →(second 1/2 life) 125 g →(third 1/2 life) 62.5 g →(fourth 1/2 life) 31.25 g →(fifth 1/2 life) 15.625 g
So, The amount remained is 15.625 g after 5 half-lives (30 hours).
<u><em>Question 2.</em></u>
- The formula of Copper (II) Fluoride tetra hydrate is CuF₂.4H₂O.
- the molar mass of Copper (II) Fluoride tetra hydrate is the sum of the atomic masses o each element.
- molar mass of 1 mol of CuF₂.4H₂O = 64 + 2*(19) + 8* (1) + 4*(16) = 174 g/mol.
- molar mass of 4 mol of H₂O = 8*(1) + 4*(16) = 72 g/mol
- 1 mol of Copper (II) Fluoride tetra hydrate → 4 mol H₂O
mass % of water = (mass of 4 mol of H₂O) / (mass of 1 mol of CuF₂.4H₂O ) *100 = (72 /174) *100 = 41.4 %
<em><u>Question 3. </u></em>
<u>Mass percentage</u> is defined as the mass of a solute divided by the total mass of the solution, multiplied by 100
- mass percent = ( mass of solute / mass of solution) *100
∴ 16 = ( mass of solute / 400 g) *100
mass of solute = (16* 400)/ 100 = 64 g.
So the right choice is C. 64 grams.
Molarity of solution = 0.08 M
<h3>Further explanation </h3>
Molarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution
Where
M = Molarity
n = number of moles of solute
V = Volume of solution
Volume of solution = 100 ml + 150 ml = 250 ml