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Answer:
The 3 example of physical change are melting an ice cube, breaking a bottle, and boiling water. The 3 example of chemical change are cooking an egg, baking a cake, rusting a iron.
Explanation:
It is classified as physical /chemical change because chemical change can produce new substances, but a physical change does not.
Answer:
third
Explanation:
because it's the right distance for life to utilise the sun's power energy
<h3>
Answer:</h3>
Limiting reagent: Potassium iodide
Mass of the precipitate (PbI₂) is 4.453 g
<h3>
Explanation:</h3>
We are given;
- 60.0 mL of 0.322 M potassium iodide
- 20.0 mL of 0.530 M lead () nitrate
We are required to identify the limiting reactant and determine the mass of the precipitate formed.
<h3>Step 1: Write the balanced equation for the reaction</h3>
- The balanced equation for the reaction between potassium iodide and lead (II) nitrate is given by;
2KI + Pb(NO₃)₂ → 2KNO₃ + PbI₂(s)
<h3>Step 2: Determine the number of moles of the reagents</h3>
Moles of KI
Moles = Molarity × volume
Moles of KI = 0.322 M × 0.060 L
= 0.01932 moles
Moles of KNO₃
Moles = 0.530 M × 0.020 L
= 0.0106 M
From the equation;
- 2 moles of KI reacts with 1 mole of Pb(NO)₂
- Therefore; 0.01932 moles of KI will require 0.00966 moles of Pb(NO₃)₂
- This means, KI is the limiting reagent while Pb(NO₃)₂ is the excess reagent.
<h3>Step 3: Determine the mass of the precipitate PbI₂</h3>
2 moles of KI reacts to produce 1 mole of PbI₂
Therefore;
Moles of PbI₂ = Moles of KI ÷ 2
= 0.01932 moles ÷ 2
= 0.00966 moles
But molar mass of PbI² is 461.01 g/mol
Therefore;
Mass of PbI₂ = 0.00966 moles × 461.01 g/mol
= 4.453 g
Therefore, the mass of the precipitate formed (Pbi₂)is 4.453 g
Answer:
Natural BGH and rBGH both increase the level of another hormone called insulin-like growth factor (IGF-1) in the cow.
Beef cattle are often given steroids to increase and speed growth. Common steroids include:
-
Natural steroids like estradiol, testosterone, and progesterone
- Man-made steroids from compounds
Major groups such as FDA and Food and Agricultural Organization state track level of hormones in food. They state that the levels of hormones in food are safe to eat. Not everyone agrees.
Explanation:
Hormones are present in all animal products. Some are natural, others may be added through supplements. Hormones and steroids are given to livestock. It can increase the number of dairy products and beef.
FDA establishes the acceptable safe limits for hormones in meat. A safe level for human consumption is a level of drug in the meat that would be expected to have no harmful effect in humans based on extensive scientific study and review.