Chemistry blog #1

The main ideas that we have been focusing on, in Chemistry, so far are, matter,mass, volume, density, significant figures, zeroes and measuring all of those things. We have looked at the relationship between matter and mass, mass and volume, density and mass, and density and volume. In exploring matter and mass, we learned that matter is what everything is made out of, it takes up space, its composed of atoms and elements, and it has 3 forms, solid,liquid, and gas. Then we learned that mass is the amount of something, or how much space something takes up. That is the difference between matter and mass. To explore mass a little bit more, we did a lab called the Mass and Change lab. In that lab we massed different items, then changed them either chemically or physically and massed them again. This helped us understand how and why mass may or may not change, for different reasons.Then we compared mass and weight, and came to a conclusion that weight and mass are very different, weight is how much something weighs and mass is how much space something takes up, and mass doesn't change no matter where you are. For example, being on the moon would change your weight but not your mass because there is still the same amount of matter. Next, we looked at the relationship between volume and mass. Volume is more of how much space something has, or can be filled up with, almost. For example, a jar has a certain amount of matter, which is its mass, but how much it can be filled up, is its volume, That can be tested by the water displacement test.We did another lab on volume. In the lab, we had 5 objects and we measured the volume of them in 2 different ways, using measurements and formulas, and then using water. This lab just gave us 2 different ways to measured volume and which way is more accurate. After that, we moved onto density. Density is how dense, or compact something is.  Density, mass and volume are all different but they do relate to eachother quite a bit. The equation for density is Density= Mass/Volume, so in order to find the density of something, you need the mass and volume. Or, if you have the volume and density, you can find the mass by rearranging the equation to look like this; Mass=Density x Volume. Then we started talking about measuring correctly, significant figures are zeroes. To measure correctly, you can't measure too many decimal places beyond where the gradations on the measuring tools go. So lets say on a graduated cylinder the gradations are at every ones place, you are only allowed to measure to the tenths place and no beyond that. The number in that tenths place is the uncertainty of the measurement. For significant figures and zeros, we learned a number of rules about them. 

1. Non zeros are always significant
2. Sandwich Zeroes/ Captive Zeroes are always significant (103)
3. Leading Zeros are not significant
4. Decimal Trailing Zeroes are significant
 5. Whole number trailing are not significant