The percentage of Calcium carbonate in chalk = 100%
<h3>Further explanation</h3>
Given
1.51 g piece of chalk produces 0.665 g of carbon dioxide
Required
percentage of calcium carbonate
Solution
Reaction
CaCO3 (s) + 2 HCl (aq) → CaCl2 (aq) + H2O (l) + CO2 (g)
mol CO2 :
= 0.665 g : 44 g/mol
= 0.015
From the equation, mol CaCO3 = mol CO2 = 0.015
mass CaCO3 :
= mol x MW
= 0.015 x 100
= 1.5 g
<h3>
Answer:</h3>
B) partial pressure of oxygen
<h3>
Explanation:</h3>
- All tissues and cells in the body require oxygen to carry our respiration for the provision of energy in the form of ATP.
- Oxygen is exchanged in the lungs and is loaded into hemoglobin, a pigment in the red blood cells that carries oxygen in the tissues. This occurs through simple diffusion that is facilitated by a concentration gradient.
- In the tissues, internal respiration takes place where oxygen is unloaded from hemoglobin and diffuses into nearby cells. Diffusion occurs as a result of the difference in the partial pressure of oxygen in the blood vessels and that in the blood tissues.
- The partial pressure of oxygen in the blood vessels is higher compared to partial pressure in the cells, thus, the oxygen gas will diffuse into the cells.
Answer
30
Explanation:
literally just did that test
Answer: C a substance that can dissolve other substances
Explanation: A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature
Hope this helped
:D
Answer:
The student failed to rinse the buret with KMnO₄ solution after rinsing it with distilled water.
Explanation:
In a titration, the equivalent moles of titrant must be the same than analyte. If the student calculates an amount of moles of H₂O₂ that is larger than the actual value:
The student failed to wear goggles <em>FALSE. </em>The use of goggles doesn't change the results in the lab but you must use it!
The student did not swirl the flask appropriately and therefore stopped short of the endpoint. <em>FALSE. </em>The stopped short of the endpoint would explain a lower concentration of the real value.
The student failed to rinse the buret with KMnO₄ solution after rinsing it with distilled water. <em>TRUE. </em>If you don't rinse the buret with KMnO₄ solution the concentration of this solution in the buret will be lower than real concentration doing you spend more titrant volume overestimating the amount of H₂O₂ moles.
The student added an extra 15 mL of distilled water to the H₂O₂ solution. <em>FALSE. </em>The addition of water doesn't change the amount of H₂O₂ moles in the solution.
I hope it helps!