3.
1 answer:
Answer:
14.7838
Explanation:
Given that;
A student uses a solution that contains 16 g of water to conduct an experiment and at the end of an hour ; the amount have decreased by 3.5%
The mathematically illustration for this is given as
= 16 g × 3.5%
=
= 0.56
After an hour; the amount have decreased by 16 - 0.56
= 15.44
after 2 hours the water decreased by another 4.25%
i.e
⇒ 0.6562
after two hours , the amount would have decreased by:
= 15.44 - 0.6562
= 14.7838
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Answer:
0.714 liter.
Explanation:
Given:
The balloon initially has a volume of 0.4 liters and a temperature of 20 degrees Celsius.
It is heated to a temperature of 250 degrees Celsius.
Question asked:
What will be the volume of the balloon after he heats it to a temperature of 250 degrees Celsius ?
Solution:
By using:
Assuming pressure as constant,
V∝ T
Now, let K is the constant.
V = KT
Let initial volume of balloon , = 0.4 liter
1000 liter = 1 meter cube
1 liter =
0.4 liter =
And initial temperature of balloon, = 20°C = (273 + 20)K
= 293 K
Let the final volume of balloon is
And a given, final temperature of balloon, is 250°C = (273 + 250)K
= 523 K
Now, =
=
Dividing equation 1 and 2,
K cancelled by K.
By cross multiplication:
Now convert it into liter with the help of calculation done above.
Therefore, the volume of the balloon be after he heats it to a temperature of 250 degrees Celsius is 0.714 liter.
<u>Answer:</u> When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The overall chemical reaction follows:
The intermediate balanced chemical reaction are:
(1)
(2)
The expression for enthalpy of the reaction follows:
Hence, when the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.