Q unknown = -Q H2O
Q H2O= (100g x 4.18 J/g C x (25C - 20C)
Q H2O = 2090J
-2090J = (50g x c x (25C-90C)
-2090J = -3250c
.64 = c
I am a high school student and have done this problem a few months ago for my test, hope this helps
A crushed garlic will have a lot of flavor when placed in food due to the surface area that is in contact with the food. When we have a large piece of garlic, only the external part touches the food and its full capacity is not used. When we reduce the size of the year by crushing the internal parts that were not in contact with the food, now they will be, in addition, liquids are also released due to the pressure exerted on the garlic and these liquids mix more easily with the food and they give it more flavor. For better understanding we can see the following figure:
Simply to understand it, in the figure, there is a clove of whole garlic represented by the rectangle that will have a height of 3 and a width of 1, the units do not matter in this case. The area that is in contact will be equal to 8, but if we divide the garlic into three equal parts, it will have a contact area greater than 12. Therefore, the more we divide the garlic, the more area it will be in contact with the food and will give it more flavor.
For #2: Odor, Temperature, and color
Answer : The correct option is, +91 kJ/mole
Solution :
The balanced cell reaction will be,
Here copper (Cu) undergoes oxidation by loss of electrons, thus act as anode. Lead (Pb) undergoes reduction by gain of electrons and thus act as cathode.
First we have to calculate the standard electrode potential of the cell.
Now we have to calculate the standard Gibbs free energy.
Formula used :
where,
= standard Gibbs free energy = ?
n = number of electrons = 2
F = Faraday constant = 96500 C/mole
= standard e.m.f of cell = -0.47 V
Now put all the given values in this formula, we get the Gibbs free energy.
Therefore, the standard Gibbs free energy is +91 kJ/mole