Chemistry Reflection 8

Today in Chemistry we learn and review about ionic bonding. We review on how atoms consist of 3 types of subatomic particles which are protons, electrons and neutrons. While proton is +, neutron is neutral and electron is -. We learn that metal atoms are positive ions or cations. Also, non-metals are negative ions or anions. We learn about charge so an atom that has a nearly empty outer shell, it will take less energy to lose electrons so it will be positive. While an atom that has a nearly full outer shell will take less energy to gain electrons so it will be negative.  

Chemistry Reflection 7

Today in Chemistry, we did an experiment on empirical formula which is to find how many water in hydrated copper sulfate (H₂0 in CuSO₄).

So first we need to weigh the crucible (24.54 grams) and then we need to fill it with 2 grams of copper sulfate. Then we need to burn it. After heating it we need to let it cool down. We need to weigh it again and subtract it with the weight of the crucible. (24.54 – 23.35 grams) That will be the mass of the copper sulfate (1.19 grams).

Then we subtract it with 2 so it is (2-1.19) so the mass of water is 0.81 grams. Then you will need to find the empirical formula which will be 1:5 

Chemistry Reflection 6

Today in Chemistry, we learn about empirical formula and molecular formula. While empirical formula is just an estimation of the number of atoms in an element, molecular formula is like exact. The way to find it is also similar.

To find an empirical formula, you need to know the mass so for example

Calcium=36.1 grams

Chlorine = 63.9 grams

After we know the grams, we need to divide by the molar mass

Calcium =

Chlorine =

Now we need to divide both numbers with the smallest equation which is 0.9

0.9/0.9 = 1

1.8/0.9 = 2

So the ratio is 1:2 so it is CaCl₂

To find the molecular formula you need the molar mass of the compound and then just repeat the process to find the exact ratio.

Chemistry Reflection 5

Today in Chemistry, we learned about moles. In chemistry, moles are 6.02 x 10²³ and this is the Avogrado number which is used to find the number of moles. There is also a process which is

Number of Particles (N)= Number of moles (n) x Avogrado Number (N_A).

An example is:   10.1 grams = 0.1 moles x 100.1 grams/mol.

Mass= Number of moles x molar mass

The molar mass is basically just the Ar or Mr. This can be found on the periodic table

Chemistry Reflection 4

Today we learned about balancing equations. Balancing equations is when there is a chemical equation but the elements in the equation are not equal so we need to balance them. An example is :

AgI+Na₂S=Ag₂S+NaI

The elements are not balanced because there are 2 sodium in the first one and only 1 in the second one. We fix it by multiplying the second one by 2. Also, there are 2 silver in the second one while only one in the first one so we multiply the first one by 2 to make this.

2AgI+Na₂S=Ag₂S+2NaI

It is kinda difficult because sometimes we get the numbers wrong and we need to try again. The easiest way to do it is to change the number of the lone element first. So if there is an element that is not mixed with another element, change it first so it is easier.

Chemistry Reflection 3

Today, we learned more about relative molecular mass and relative atomic mass. We had to do a worksheet on relative molecular mass.  So to find the relative molecular mass we need to find the relative atomic mass of all the elements in a compound and then add them so it's like

H₂O

H₂: 1 x 2

O: 16 x 1

16+2=18 gr/mol

The number that goes first is the relative atomic mass so the relative atomic mass of hydrogen is 1 while oxygen's is 16. The second number shows how many of the atoms of the elements are there, So, this means that are only 1 atom of oxygen while there are 2 atoms of hydrogen.

Chemistry Reflection 2

Today, we learned about relative atomic mass and relative molecular mass. Relative molecular mass  is like the sum of atomic mass in a compound so for example H₂O. H₂ is (1x2) while O is 16 so it will be 18 gr/mol. Relative atomic mass is the molecular weight of an atom so it’s the average mass of an atom in an element. So for example Oxygen is 16 while Nitrogen is 14. It’s basically the number in the bottom of the periodic table