2KF(s) -----> 2K(s)+F2(g)
Answer: 0.771 g of 
will be produced
Explanation:
To calculate the moles :
The balanced chemical reaction is:
According to stoichiometry :
2 moles of 
produce = 3 moles of
Thus 0.257 moles of will produce=
of
Mass of 
Thus 0.771 g of will be produced
The given question is incomplete. The complete question is:
Which is true of Elements on a periodic table in the same group (family)?
A; Elements in the same family have similar chemical properties because they have the same number of electron shells.
B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.
C; Elements in the same family have few similar properties as they have different numbers of electron shells.
D; Elements in the same family are always the same type of Elements and have the same number of protons.
Answer: B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.
Explanation:
Elements are distributed in groups and periods in a periodic table.
Elements that belong to same groups will show similar chemical properties because they have same number of valence electrons.
The chemical reactivity of elements is governed by the valence electrons present in the element.
Example: Flourine, chlorine and bromine are elements which belong to Group 17. They have 9, 17 and 35 electrons respectively and contain 7 valence electrons each and need one electron to complete their octet.
Explanation:
Molar mass of 
= 39.1 + 35.5 + 3(16.0) = 122.6 g
Molar mass of KCl = 39.1 + 35.5 = 74.6 g
Molar mass of 
= 32.0 g
According to the equation, 2 moles of reacts to give 3 moles of oxygen.
Therefore, 2 (122.6) = 245.2 g of will give 3 (32.0) = 96.0 g of oxygen. Thus, 245.2 g of gives 96.0 g of oxygen.
(a) Calculate the amount of oxygen given by 2.72 g of as follows.
of
(b) Calculate the amount of oxygen given by 0.361 g of as follows.
of
c) Calculate the amount of oxygen given by 83.6 kg as follows.
of
Convert kg into grams as follows.
= 32731 g of
(d) Calculate the amount of oxygen given by 22.5 mg of as follows.
Convert mg into grams as follows.
of
Answer:
Law of conservation of mass
Ernest Rutherford
Explanation:
The basic law of behavior of matter that states that "mass is neither created nor destroyed in a chemical reaction or physical change".
This is the law of conservation of mass. It is very essential in understanding most chemical reaction. Also, in quantitative analysis, this law is pivotal.
Ernest Rutherford was the scientist that stated that the nucleus is made up of positive charge. It was not until James Chadwick in 1932 discovered the neutron that we had an understanding of this nuclear component.
Rutherford surmised from his experiment that because most the alpha particles passed through the thin Gold foil and just a tiny fraction was deflected back, the atom is made is made up of small nucleus that is positively charged.
