Answer:
pH =1 2.84
Explanation:
First we have to start with the <u>reaction</u> between HCl and KOH:
Now <u>for example, we can use a volume of 10 mL of HCl</u>. So, we can calculate the moles using the <u>molarity equation</u>:

We know that
and we have the concentration of the HCl
, when we plug the values into the equation we got:



We can do the same for the KOH values (
and
).



So, we have so far <u>0.00282 mol of HCl</u> and <u>0.00705 mol of KOH</u>. If we check the reaction we have a <u>molar ratio 1:1</u>, therefore if we have 0.00282 mol of HCl we will need 0.00282 mol of KOH, so we will have an <u>excess of KOH</u>. This excess can be calculated if we <u>substract</u> the amount of moles:

Now, if we want to calculate the pH value we will need a <u>concentration</u>, in this case KOH is in excess, so we have to calculate the <u>concentration of KOH</u>. For this, we already have the moles of KOH that remains left, now we need the <u>total volume</u>:

Now we can calculate the concentration:


Now, we can <u>calculate the pOH</u> (to calculate the pH), so:
Now we can <u>calculate the pH value</u>:
Answer:
1,100,160J or 262.94 kcal
Explanation:
The juice is frozen at 0 degrees Celsius and I assume that it will become gas at 100 degrees Celsius. So we change the form of the water from solid to liquid, then to gas. That means we have to find out how much heat needed to change water form too, not only the heat needed to increase its temperature.
The latent heat of water is 4.2J/g °C while the heat of fusion is 334 J/g and the heat of vaporization is 2260 J/g. The energy needed will be:
360g * 4.2J/g °C * (110-0°C ) + 360g * 334 J/g + 360g * 2260 /g = 1,100,160J or 262.94 kcal.
Answer:
Explanation:
a) In an exothermic reaction, the energy transferred to the surroundings from forming new bonds is ___more____ than the energy needed to break existing bonds.
b) In an endothermic reaction, the energy transferred to the surroundings from forming new bonds is ___less____ than the energy needed to break existing bonds.
c) The energy change of an exothermic reaction has a _____negative_______ sign.
d) The energy change of an endothermic reaction has a ____positive________ sign.
The energy changes occur during the bonds formation and bonds breaking.
There are two types of reaction endothermic and exothermic reaction.
Endothermic reactions:
The type of reactions in which energy is absorbed are called endothermic reactions.
In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.
For example:
C + H₂O → CO + H₂
ΔH = +131 kj/mol
it can be written as,
C + H₂O + 131 kj/mol → CO + H₂
Exothermic reaction:
The type of reactions in which energy is released are called exothermic reactions.
In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.
For example:
Chemical equation:
C + O₂ → CO₂
ΔH = -393 Kj/mol
it can be written as,
C + O₂ → CO₂ + 393 Kj/mol
Answer:
density=1.43 g/L
Explanation:
Since the density formula is density = mass / volume, we need to find out the mass of the gas and the volume is that of the container.
The mass of the gas is 130.0318 g-129.6375 g=0.3943 g
The gas volume is 276mL*(1L/1000mL) 0.276 L
density = mass / volume=0.3943g/0.276L
density =1.43g/L