There are *219,000* hours in 25 years
Answer:
pH = 2.21
Explanation:
Hello there!
In this case, according to the reaction between NaF and HCl as the latter is added to the buffer:
It is possible for us to see how more HF is formed as HCl is added and therefore, the capacity of this HF/NaF-buffer is diminished as it turns acid. Therefore, it turns out feasible for us to calculate the consumed moles of NaF and the produced moles of HF due to the change in moles induced by HCl:
Next, we calculate the resulting concentrations to further apply the Henderson-Hasselbach equation:
![[HF]=\frac{0.450mol}{1.0L} =0.450M](https://tex.z-dn.net/?f=%5BHF%5D%3D%5Cfrac%7B0.450mol%7D%7B1.0L%7D%20%3D0.450M)
![[NaF]=\frac{0.050mol}{1.0L} =0.050M](https://tex.z-dn.net/?f=%5BNaF%5D%3D%5Cfrac%7B0.050mol%7D%7B1.0L%7D%20%3D0.050M)
Now, calculated the pKa of HF:
We can proceed to the HH equation:
![pH=pKa+log(\frac{[NaF]}{[HF]} )\\\\pH=3.17+log(\frac{0.05M}{0.45M} )\\\\pH=2.21](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%28%5Cfrac%7B%5BNaF%5D%7D%7B%5BHF%5D%7D%20%29%5C%5C%5C%5CpH%3D3.17%2Blog%28%5Cfrac%7B0.05M%7D%7B0.45M%7D%20%29%5C%5C%5C%5CpH%3D2.21)
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<span>
1. Which of the following is a part of a land-based carbon cycle?
Trees
Whales, crab shells, and coral reefs would be part of the ocean-based carbon cycle. Trees roles in the carbon cycle are to catch carbon in the atmosphere (in carbon dioxide forms) and do photosynthesize to create carbohydrate.
Shells are reefs hard skeleton is consist of inorganic carbon that mostly made by CaCO3(calcium carbonate) compound.
2. X represents a substance in a plant involved in photosynthesis. What is its role?
</span><span>It traps light energy and converts it into chemical energy.
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6CO2 + 6H2O + light energy = C6H12O6 + 6O2.
The main product of photosynthesis is a carbohydrate, which is the main energy source for living organism. From the equation, you can see that A is water and B is carbohydrate.
To produce carbohydrate, photosynthesis needs energy that was provided by the sunlight. The plant has a substance that could convert light into chemical energy called chlorophyll that was stored inside chloroplasts cells. The X above the arrow is chlorophyll<span>.
</span><span>
3. What type of energy transformation takes place when carbon is cycled in a gasoline-based car?
Chemical energy to mechanical energy
The gasoline will undergo combustion process which will produce heat and mechanical energy in the piston of the machine. The energy desired would be mechanical energy and the thermal energy is just side product.
4. Which of the following statements would correct one of the roles listed in the table?
Water combines with carbon dioxide during photosynthesis.
On the photosynthesis equation I mentioned above, water and carbon dioxide is the reactant of the photosynthesis. They both will be combined to produce carbohydrate(sugar) and water molecules.
Chrolophyll is not part of the reaction. It just provides the energy needed for the reaction.
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5. Which of the following processes does not take place during cellular respiration?
Hydrogen of water is separated from oxygen.
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In cellular respiration, the cells using the carbohydrate to produce energy.
The reaction is similar with photosynthesis with reversed product and reactant.
C6H12O6 + 6O2 --> 6H2O + 6CO2 + ATP.
As you can see in the equation, cellular respiration is not using water but produce it instead. It doesn't produce hydrogen either. <span>
6. Using the above equation, how would you prove the law of conservation of mass?
By showing that the numbers of atoms of the same type are equal on both sides.
</span>The law of conservation of mass state that mass can't be produced. That means the reactant and product mass should be same.
The law can be proved by comparing the number of atoms from each element in reaction. The product should have the same number of atoms of the same type with the reactant
<span>
7. During which of the following processes would carbon most likely be required?
Making of glucose
Glucose is carbohydrate that was made of carbon, hydrogen, and oxygen. Since glucose contains carbon, it is most likely to require carbon to make glucose.
</span><span>
Breaking of rocks, generation of electricity, and running of cars need energy that can be gained from various ways.</span>
