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Answer:</h3>
B) partial pressure of oxygen
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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:
The correct answer is:
<em>(1) It is important that the sample is dissolved in just enough hot solvent. </em>
Explanation:
The process of recrystallization is important to eliminate the impurities and to obtain better crystals of the solid. The solvent used to perform the recrystallization must have a high dissolution power of the substance to be recrystallized and a low dissolution power of the impurities. This is in order to eliminate most impurities. Furthermore, <em>It is important that the sample is dissolved in just enough hot solvent </em>because this should be easy to remove after the recrystallization and the crystal should form easily when the solution cools. Also, it is better to add the hot solvent to solubilize the crystals and keep the impurities insoluble, instead of adding the cold solvent and heating the solution. Additionally, the process of cooling the solution must be done slowly to obtain large and fewer crystals. A fast ice-cooling will form smaller crystals.
Answer:
ΔHr = -275 kj
Explanation:
It is possible to obtain the net change in enthalpy for the formation of one mole of lead(II) sulfate from lead, lead(IV) oxide, and sulfuric acid using the reactions:
(1) H₂SO₄(l) → SO₃(g) + H₂O (l) ΔH=+113kJ
(2) Pb(s) + PbO₂(s) + 2SO₃(g) → 2PbSO₄(s) ΔH=−775kJ
If you sum (1) + ¹/₂(2) you will obtain:
H₂SO₄(l) + ¹/₂Pb(s) + ¹/₂PbO₂(s) → PbSO₄(s) + H₂O(l)
Using Hess's law, the net change in enthalpy for this reaction could be obtained as:
ΔHr = ΔH(1) + ¹/₂ΔH(2)
ΔHr = +113kJ + ¹/₂ -775kJ
ΔHr = -275 kJ
Answer:
The number of molecules = 2.6408 molecules
Explanation:
To determine the number of molecules in water, we need to determine how many moles of water we have
Water has a molar mass of 18.015g/mol, this means that one mole of water molecules has a mass of 18.015g
To find the number of molecules,
7.9g * 1 mole H2O/ 18.015g
= 0.4385mole of H2O
Using avogadro number,
0.4385 H2O * 6.022* 10^23molecules/ 1 mole of H2O
That's 0.4385 H2O multipled by 6.022*10^ 23 molecules divided by 1 mole of H2O
Which gives == 2.6408 molecules
The liquid freezes at 32 degrees celcius(A) is not the properties of water as water freezes at 0 degrees celcius