Thursday, April 24, 2014

Reflection about Ionic and Covalent Bond by Alda 8A


Ionic bond is a chemical bond (metal with non metal) in which one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion. While on the other hand, covalent bond is a chemical bond (non-metal with non-metal) that involves sharing a pair of electrons between atoms in a molecule. How to illustrate an ionic bond is by using a cross and dots to indicate the electrons, using brackets for every element you draw and write the charge at the right top of the outside bracket. Also put the name of the element for the first shell. On the other hand, to illustrate the covalent bond, you just need the last shell and it'll look like venn diagram and the intersection between the shells (the middle part) is for you to put how many electrons are shared among them.

The examples of a covalent bond is like NH3 and also CH4.

 The example of ionic bond is NaCl and also MgO.

Wednesday, April 9, 2014

Reflection term 3 Alda 8A

I had a lot of challenges studying chemistry in this 3rd term since the topic gets more difficult. How do I manage it is of course by studying. And especially for the difficult topic like solving empirical formula, I need to understand it by asking to either Ms. Neri or my friends. Not only that, when learning balancing equation, I need to be extra careful even though it's not difficult. What I found interesting in this 3rd term is learning how to calculate Mr of a compound because it's so much easier than the other topic but it really requires you to focus because it's easily to get miss calculated. Actually I don't accomplish my goal. But I think I've already try to give my best even though the score isn't that satisfying, from the mistakes I made when I did the quiz, now I know that I need to be careful and the thing I really need to improve on is to always be careful and double check because the little things matter. My goal for the rest of grade 8 is to always give my best and keep up my score at least above 9. How am I going to achieve it is by studying and practicing because since the topic gets harder, I need to cope with it and since I like to keep things to myself, I think I need to be more open and ask for help if I don't understand the topic or when I have difficulties. I think I need to study more than before especially if there's a test I need to study few days before so I can understand it better and achieve my best.

Wednesday, January 22, 2014

#Reflection 2

In this chemistry lesson I learned about describing the chemical formula of compound from the relative number of atom present. I learn the difference between the monoatomic and polyatomic element. Monoatomic is when we're combining two single element (metal and non metal) such as N and the atomic mass charge is +1 and O with charge of -2. But polyatomic element is we combine two element (non metal and metal) but the non-metal is with both charge for atomic number and atomic mass. The non-metal element of the monoatomic will be change with ide in the back of the word (oxygen become oxide). But the non-metal element of the polyatomic will be change with ate or ite in the back of the word (depends on the charge of the atomic number and atomic mass). I also learn to find the number of atom in the chemical formula of compound. for example if we react Na+1 with O-2 it will become Na2O so there are 2 atoms of Na and 1 atom of O. Another example is if we combine Li+1 with CO-2 (atomic mass) +3(atomic number) it will become Li2CO3 which is lithium carbonate. And we know that there are 2 atoms of lithium and 1 atom of carbon with 3 atoms of oxygen. However if the formula of the monoatomic is Cu(OH)2, we need to multiply 2 with the inside of the bracket which is O and H, which means there are 1 atom of copper, 2 atoms of oxygen and 2 atom of hydrogen. And if the formula of the polyatomic is CuSO4 . 5H2O, we need to multiply 5 with 2 for the H and move 5 to O, so it will become 1 atom of copper, 1 atom of sulphur, 9 atoms of oxygen and 10 atoms of hydrogen.






Friday, January 17, 2014

Reflection #1 (Alda8A)

Today, 16 January 2014.

Today in chemistry lesson I learn about how to write chemical formula and naming compound, in this case we are reacting metal with non-metal. These are some examples I learned during the chemistry lesson:

For example we want to react Sodium with Sulphur, the first thing we need to know is the oxidation number of each of the element by looking through the periodic table (the group number), from left to right, the oxidation number for each row will be +1, +2, (and skip the transition metals) +3, +4, -3, -2, -1, 0. After determining the oxidation number of each element, sodium (Na) is +1 because its the most left and sulphur (S) is -2 because its the 6th rows. We know that sulphur has a bigger number of oxidation, we need to cross multiply the number of oxidation for each of element. So Na+1 S-2 will become Na2S after we cross multiply which means now there are 2 sodium and 2 sulphur which means that its balanced.

I also learn that if the element is monoatomic, like Nitrogen (N), Oxygen (O) etc, we need to change the last words using "ide" so if its nitrogen, it'll become nitride, oxygen become oxide. However if its polyatomic like Na3, the nitrogen will be replaced with ate so it becomes nitrate. If Na2 it'll become nitrite.

Sunday, January 12, 2014

Chemistry Semester 2 Goals (Alda8A)

In this school semester 2, I want to improve a lot in chemistry because previous semester my score wasn't really satisfying. My score is decreasing on semester 1 term 2 which makes me want to work harder to achieve a better score for this semester. I want to get at least another 9.7 more and I know I can because I managed to get 9.7 in semester 1 term 1, so I believe that if I keep on trying, practicing and studying I am capable of getting more. How am I going to achieve my goal?

How am I going to achieve my goal is by studying hard. I need to listen more to the teacher when they're explaining, trying not to chat with my friends when the teacher is explaining so I can carefully understand the concept of the subject. And maybe I need to take some courses to help me study individually outside the school hours. And its important that I put more effort when making my homework and when I'm studying so that I give my best so I won't regret the score because previously in semester 1 term 2, my score is decreasing because I don't get perfect scores in my homework like I got perfect scores in semester 1 term 1. I need to study not only the night before I had a test/quiz, I need to study couple of days before to make sure that I am well prepared.

Of course getting 9.7 more on my report is not an easy thing to achieve, but I know what I'm capable of doing if I try harder. I know it's hard to get the score I want, but you will not achieve it if you don't try to because getting the best is never an easy thing to do.