Basic chemistry Definition and 23 Threads

ik this is basic knowledge, that all groups go up in reactivity the further down you go in the group, except for group 7, where this is reversed. however i don't understand why, because in group 7, the electron shielding still increases the further down the group you go, like with all the other...

Hi everyone, I just don't get it how to compute the following task. First I have to find out many moles are in 27g of Water. H2O = 2*1.01 + 16 = 18.02 27g/18.02 = 1.5mol but afterwards how do I find each elements gram? d is the correct answer.

Let's think now about the energy to create a KF molecule from neutral atoms. First we need to ionize both K and F: K loses an electron and F gains an electron. Then we have to bring the ions together. The first ionization energy of K is 418 kJ/mol and for F is 1681 kJ/mol. The electron...

Hi everyone, I am a 10th grade student studying in India( would be in 11th in 2 months)I am not very good at chemistry. I have difficulty understanding the concepts. Although I don't have any doubts, I just don't feel confident. Also, my teacher is not very good. Whenever I would ask him...

Hi I am new to the concept of neutralization. My teacher told me that acids do not react with neutral salts. I want to know why not. If both are dissolved in water and both completely dissociate, why can't the ions of acid and salt exchange and perform a double displacement reaction. Moreover I...

Doubts regarding the law of reciprocal proportions: What i have understood by reading the definition is that the ratio of the masses in which two elements A and B combine with a fixed mass of a third element C, will be a whole number multiple of the ratio of the masses in which A and B combine...

I am looking for a very concise book on chemistry that is under or equal to 300 pages.

This is a concept I have never really understood. I mean to say is how can we include such a thing in a theory? How can we use them if we know that they don't actually exist? Are they some sort of calculation tool?

Hello, I was wondering if anyone could help to explain something simple to me, I am lost for answers, and this is something a 7th grader should know I am assuming. C2H2 + N2O ---> CO2 + N2 + H2O. Now this may seem like a retarded question, but how can there be two oxygen molecules in the...

Hello everyone, This site is so beautiful. There's an overwhelming amount of information and resources. It is a future scientist's dream to come across this site. I have fully committed to my goals of going further in physics and I am taking it a step up today due to posting here. My knowledge...

Basic chemistry: sulphur dioxide shape??! I realize this isn't homework, but it's so basic I'm ashamed of putting it in the chemistry section. I'm trying to self-teach here, but my textbook is awful and I'm even worse. Question: Workout the shape of SO2. Step 1: Draw lewis diagram to work out...

In our high school Chem 1 Class, we had this lab where we went around doing simple experiments and determining whether the change was a physical one or a chemical one. Well, when one of the stations had be perplexed. At this station we had a Nickel Chromium Wire with an Aluminum...

The problem statement: Complete the following table: Symbol: Element Name: Atomic #: Mass # # of Protons # of Neutrons # of Electrons 34 Sulfur S 16 I am confused how they got the # 34 above S. The atomic # is 16 and atomic weight is 32. How did they...

Hello, As the title should have implied, I am looking into the possibility of learning some basic chemistry on my own. My background in the subject is minimal, consisting primarily of the very little I've had in the earlier high school grades -- and frankly, I have not the slightest of ideas...

Homework Statement Given a table of percentages. One column stands for the percent of Nitrogen in a substance, the other a percent of Oxygen. Given the table (4 rows with different values), figure out the ratio of atoms of Oxygen for a given amount of Nitrogen. Homework Equations...

Hello. I just started a first year chemistry course after switching to the sciences from the arts, and wanted to double-check some equations with you because this is a little new to me. I'm good with the qualitative stuff, but the quantitative parts come a little harder. Q1: A sheet of metal...

I an a older student that would like to go back to college. I want to teach myself basic chemistry before i go back. Could anybody recommend a book, tutoring software, or website that can help accomplish this task?

Hey guys I need some help on some chemistry questions (any help will help) 1. Is it more correct to write H+ (aq) or H3O+(aq)? Explain. Now, as far as I know, these both mean the same thing, but we'd prefer to write H+ to help understand pH level right? I'm not too sure. 2. In words, what...

Ok there is a mixture of hydrogen and chlorine molecules in a container. I need to compare a)the temperature of each gas, and b)the average kinetic energy of the molecules without doing any calculations. a) I'm not sure I should answer with T=PV/nR for each one or whether i should...

Well, hello! I was informed a new formula. As a non-native, I can't give out the definitons, I hope that you can help me call some. Well, here is the formula: \Delta=\frac{2+\Sigma n_i (V_i-2)}{2} Well, as far as I can say, \Delta here is equal to the total of the linkage C=C+ number of...

Hi I have just started grade 11 chemistry... We're reviewing from grade nine a bit and in class we did an experiment where we had copper(II) sulfate in a test tube and we heated it, and then let it cool and added water... Ok well we have to classify this as a physical or chemical change.. but...

Hi, i am a 3rd year in General Chemistry, freshmen at a university, and i have a few problems that I've encountered along the way. These questions has been bugging me for a long time now and i really hope someone can fill in the holes and gaps in for me..anyways here they are 1) Let's say...

I'm really no good at Chemistry, and these are practice questions to our test tomorrow (with no answers, which is pretty worthless ) 5. A 10mL solution of 1.0M NaOH is required to react completely with how many mL of a 0.25M solution of H2SO4? a) 20mL b) 40mL c) 160mL d) 4mL e) 10mL...