Answer:
Collision theory states that when suitable particles of the reactant hit each other, only a certain fraction of the collisions cause any noticeable or significant chemical change; these successful changes are called successful collisions.
Explanation:
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Answer:
28.93 g/mol
Explanation:
This is an extension of Graham's Law of Effusion where 
We're only talking about molar mass and time (t) here so we'll just concentrate on
. Notice how the molar mass and time are on the same position, recall effusion is when gas escapes from a container through a small hole. The time it takes it to leave depends on the molar mass. If the gas is heavy, like Xe, it would take a longer time (4.83 minutes). If it was light it would leave in less time, that gives us somewhat an idea what our element could be, we know that it's atleast an element before Xenon.
Let's plug everything in and solve for M2. I chose M2 to be the unknown here because it's easier to have it basically as a whole number already.

The square root is easier to deal with if you take it out in the first step, so let's remove it by squaring each side by 2, the opposite of square root essentially.



M2= 0.22 x 131
M2= 28.93 g/mol
Answer: The correct option is 3.
Explanation: We are given a compound which is made up of iron and oxygen only. The ratio of the two are given as:

This means that, number of iron ions are 2
Number of oxide ions are 3
From the above information, the formula becomes : 
The valency of iron = 3
Valency of oxide = 2
This compound is named as iron (III) oxide.
Hence, the correct option is 3
The mixture contains:
CaCO3 + (NH4)2CO3 in which the amount of carbonate CO3 = 60.7% by mass
Let, the total mass = 100 grams
Mass of CaCO3 = x grams
Mass of (NH4)2CO3 = y grams
Thus, x + y = 100 ------------(1)
Mass of CO3 = 60.7% = 60.7 g
Molar mass of CO3 = 60 g/mol
Total # moles of CO3 = 60.7 g/60 g.mol-1 = 1.012 moles
The total moles of CO3 comes from CaCO3 and (NH4)2CO3. Therefore,
moles CaCO3 + moles (NH4)2CO3 = 1.012
mass CaCO3/molar mass CaCO3 + mass (NH4)2 CO3/molar mass = 1.012
x/100 + y/96 = 1.012---------(2)
based on equation 1 we can write: y = 100-x
x/100 + (100-x)/96 = 1.012
x = 71.2 g
Mass of CaCO3 = 71.2 g