Answer:

Explanation:
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In this case, according to the given information, it will be possible for us to use the Dalton's law, in order to solve this problem. However, we first need to calculate the mole fraction of oxygen by firstly calculating the moles of each gas:

Next, we calculate such mole fraction as follows:

Then, given the following equation:

So we solve for the total pressure as follows:

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Ok....... why don’t u do
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Answer:
The salt is Zn(NO3)2
When the residue is allowed to cool, its colour changes from yellow to white
The equation of the reaction is; 2Zn(NO3)2(s) --->2ZnO(s) + 4NO2(g) + O2(g)
Explanation:
Decomposition of Zn(NO3)2 is one of the routes by which ZnO is obtained. ZnO is a white insoluble powder which has a yellow colour when hot and a white colour when cold. It is an amphoteric substance used as a white pigment in paints and as a filler for rubber.
In a very pure form, it is used in cosmetic powders and creams as well as in medicinal ointments and lotions.
Also recall that NO2 is a brown gas and oxygen gas rekindles a glowing splint.
17) 8.4 / 20 x 100
18) 20 . 0.5150
19) 6,50% because (as you said) the law of definite proportions states that regardless of the amount, a compound is always composed of the same elements in the same proportion by mass
A chemical reaction (signs)
- rusting
- change in base of chemical
- for example lets say u mix two chemicals, and then it becomes a different new chemical (it changed from the inside)
a physical
- a physical reaction is outer looks not inside.
- it changes on the outside, like changing a color