Answer:
b) +2 and +3.
Explanation:
Hello,
In this case, given the molecular formulas:

And:

We can relate the subscripts with the oxidation states by knowing that they are crossed when the compound is formed, for that reason, we notice that oxygen oxidation state should be -2 for both cases and the oxidation state of X in the first formula must be +2 since both X and O has one as their subscript as they were simplified:

Moreover, for the second case the oxidation state of X should be +3 in order to obtain 3 as the subscript of oxygen:

Thus, answer is b)+2 and +3
Best regards.
Answer : The temperature in degree Celsius is, 
Explanation :
The conversion used for the temperature from Kelvin to degree Celsius is:

where,
= temperature in Kelvin
= temperature in centigrade
As we are given the temperature in Kelvin is, 2.7
Now we have to determine the temperature in Kelvin.



Therefore, the temperature in degree Celsius is, 
The balanced equation that illustrates the reaction is:
2C4H6 + 11O2 ......> 8CO2 + 6H2O
number of moles = mass / molar mass
number of moles of oxygen = 2.1 / 32 = 0.065625 moles
Now, from the balanced equation, we can note that:
11 moles of oxygen are required to produce 6 moles of water.
Therefore:
0.065625 moles of oxygen will produce:
(0.065625*6) / 11 = 0.03579 moles of water
number of moles = mass / molar mass
mass = number of moles * molar mass
mass of water = 0.03579 * 18 = 0.644 grams
<u>Answer:</u> The pH of the buffer is 4.61
<u>Explanation:</u>
To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:
![pH=pK_a+\log(\frac{[\text{conjuagate base}]}{[\text{acid}]})](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%28%5Cfrac%7B%5B%5Ctext%7Bconjuagate%20base%7D%5D%7D%7B%5B%5Ctext%7Bacid%7D%5D%7D%29)
We are given:
= negative logarithm of acid dissociation constant of weak acid = 4.70
= moles of conjugate base = 3.25 moles
= Moles of acid = 4.00 moles
pH = ?
Putting values in above equation, we get:

Hence, the pH of the buffer is 4.61
1.2 x 10^10 mm^3 is equivalent to 12.0 m^3