Need some help with class work for general chemistry i solved all the questions i could but i still need these:?
(0.525 g) / (11.342 g/cm^3) / ((2.5 inches) × (2.54 cm/inch))^2 = 0.00115 cm ------------------- volume of ball bearing alone: (4/3) × π × radius^3 = (4/3) × (3.14159) × (1.00 mm / 2)^3 = 0.5236 mm^3 volume of ball bearing plus gold coating: (4/3) × (3.14159) × ((1.00 mm / 2) + 0.200 mm)^3 = 1.4368 mm^3 volume of gold alone: 1.4368 mm^3 - 0.5236 mm^3 = 0.9132 mm^3 = 0.0009132 cm^3 mass of gold alone: (0.0009132 cm^3) × (19.3 g/cm^3) = 0.0176 g Au -------------------------- 1) The element with 32 protons is Germanium (Ge). It is a metalloid. 2) (72.640 g Ge/mol) / (12.000 g C/mol) = 6.05 = 6 times 3) (0.75 carat) × (0.200 g/carat) / (12.01078 g C/mol) × (6.022 × 10^23 atoms/mol) = 7.5 × 10^21 atoms C
I need some General CHemistry 1 help?
You do not represent compounds which exist as networks with a Lewis structure. The "electron-dot notation" is for molecules. CaO is not molecular, it is a network solid with alternating calcium and oxygen atoms. So what you've been asked to do, can't really be done. Only discrete molecules are represented by a Lewis structure. As for the bonds in aluminum sulfide.... they aren't ionic. Again, someone has given you a "bum steer". Based on the electronegativity difference between Al and S, the bonds have 21% ionic character. The bonds are much more covalent than ionic. That being said, there are several different crystalline structures of aluminum sulfide in which the elements are arranged in a repeating lattice to make a network solid. Some folks mistakenly assume that a network arrangement of atoms means ionic bonds. Not the case. Network solids, which usually have relatively high melting points, can have bonds which have high ionic character all the way to bonds which are 100% covalent. Because Al2S3 is a network solid, there is NO Lewis dot structure. Again, only discrete molecules are represented by a Lewis structure.
General chemistry help?
I just need some help with some general chemistry questions. I've been trying to figure these out for a while. They aren't homework questions, but rather questions on a practice exam...and today is test day. Please help? 1. When the electron in the state n initial = 3 in the H atom undergoes a transition to a certain other n final state, ultraviolet light at a wavelength of 1.027x10^-7 m is emitted. Determine the quantum number, n final, of the state. Answer: 1 2. Which one set of quantum numbers is possible for an electron in an orbital in the 5d subshell? (in the order of n, l, m subscript l, m subscript s) a. 5, 2, -1, +1/2 b. 5, 4, 3, -1/2 Answer: A 3. A student was studying the energy transfer from hot metal to cold water. He heated 25.4 g of metal shot to 98.5 degrees C, then added it rapidly to 38.5g of water in a coffee cup caloriemeter. The final temperature of the metal and water was 28.40 degrees C. Unfortunately, the student forgot to record the initial temperature of the cold water. Given that the specific heat of metal was 0.842 J/g degrees C and that of water was 4.18 J/g degrees C, determine the initial temperature of the water. Answer : 19.1 degrees C 4. A certain element has the smallest electron affinity of all the elements. The ionization energy of this element is definiately smaller than that of Ar. It forms an anion in ionic compounds and also forms oxyacids. What is it? a. Cl b. F c. O d. Cs e. P Answer : A 5. A certain gas has the density of 0.716 g/L at STP (0 degrees C, 1 atm). Determine the molar mass of the gas and thus identify the gas. a. Ne b. CS2 c. He d. CH4 e. O2 f. HI Answer: D Thank you for any and all help! My test is in one hour, so please answer quickly if you are able!
Help with some general chemistry...?
Ok this is simple. Mass ratio is just telling you the relative amounts of one substance to another. Say you have 1 mol of MgO. That would weigh 24g + 16g which is 40g. MgO is 60 pct. Mg and 40 pct. Oxygen. The mass ratio is just 60/40 which is 1.5. Understand that the mass ratio will be the same for MgO no matter what amount of MgO you have, whether it be 1 mol of MgO or the 1.25 g u mentioned. Since MgO is 60 pct by mass, just multiply .60 times 435, which is 261 grams. If you need more help understanding just ask me.
Need help with some chem questions?
14. In general, increasing the concentrations of reactants increases the reaction rate because a. the molecular speed increases b. the entropy of the system increases c. the reaction becomes more spontaneous d. the number of effective collisions increases 15. C2H4 + Pt + H2 + heat = C2H6 + Pt What is the catalyst in the reaction above? a. C2H4 b. Pt c. H 2 d. heat e. C2H6 16. A chemical equilibrium occurs a. when the concentration of the products is the same as the reactants b. only without catalysts c. when the forward and reverse reaction rates are the same d. when the activation energy is lowered 17. Double arrows are replaced with an equal sign. A + B = C + D The reaction above is at equilibrium. What will happen if a catalyst is now added? a. the equilibrium will shift left b. the equilibrium will shift right c. the forward reaction will increase and the reverse rate will decrease d. the concentration of the reactants will equal the concentration of the products e. no correct response
Need help with some Chemistry questions?
1) Why does calcium still lose 2 electrons if it has full valence shells? 2) Why are protons almost always equal to neutrons? 3) What is the order of chemical formulas? I think the positive charge element is first, and second is the negative charge. 4) I understand the naming of ionic bonds, but what is the full list of prefixes, and suffixes. E.g.: monoxide, dioxide, etc 5) How do I say a chemical formula if it has more than two pure substances? 6) Do you always need to have the roman numerals when you are writing chemical formulas like you say it in words?
Some chem questions i need help with?
the molality of the glucose in a 1.0 molar glucose solutino can be obtained by using which of the following? a. volume of the oslution b. temp of the solutin c. solubility of glucose in water d. degree of dissociation of glucose e. desnity of the solutin 2. the radioactive decay of C (14 on top, 6 on bottom) to N (14 on top and 7 on bottom) occurs by the process of a. beta particle emission alpsha partice emission c. positron emission d. electorn capture e. teutron capture 3. when 70 mL of 3.0 molar Na2CO3 is added to 30 mL of 1.0 molar NaHCO3 the resulting concentration of Na+ is a. 2 M b. 2.4 M c. 4.0 M d. 4.5 M 7.0 M 4. what is the mole fration of ehthanol, C2H5OH in an aqueous solution in which the ethanol concetnration is 4.6 molal? a. .0046 b. .076 c. .083 d. .20 e. .72 i need help with these, not only the answer but also an explanation, if you can only or know how to do one, then please show me how, thanks
Need help with some chem?
Beta(-) will increase Z by 1, while keeping A constant. Two beta(-) decays seems to work for U-239 going to Pu-239, in which Z increases by 2 and A stays constant. The emission of a positron and electron capture both decrease the atomic number by 1. That won't work. In electron capture Z goes down by 1 and in alpha decay Z goes down by 2. Nope. In alpha decay, Z goes down by 2 and in beta(-) decay Z increase by 1. That won't work either.
What do I need to learn to understand organic chemistry?
Hm.. it's a tricky question. Often times school textbooks provide limited information and at times, it's hard to get the logic of the matter. First, you should be familiar with the structure of the atom, atomic orbitals, in particular. You need to have an idea about hybridization as it will help you see the differences in different classes of organic compounds. I don't want to assess which class is more important. Especially at school level, you are given some general idea about organic chemistry. If you are interested in pursuing a career in science, you'll get into more details and, kind of, see what's more important in a synthetic pathway. I know at first organic chemistry seems like something that you have to learn by heart. Yes, that's true for nomenclature. But, say, for hydrocarbons, if you're aware that double bonds are less stable than single bonds, you can guess that alkanes are less reactive than alkenes. You have to irradiate or heat up the former to make them react. With alkenes, reaction conditions are usually milder. Generally, it's good to know which atom in the molecule has the highest partial positive or partial negative charge. Even though covalent bonds are formed, the rule that opposites attract still applies. In carbonyl compounds, the carbon atom is partially positive, that's why electron-rich molecules will attack it, e.g. the nitrogen in amines. I'm not sure school teachers focus on this point, at least mine didn't, but I think it makes the whole learning process much easier, instead of trying to remember all kinds of reactions, when they all follow the same simple rules.Feel free to ask more questions.
Can I master chemistry on my own? And if yes, how do you suggest?
Hi there,I definitely think that with enough hard work and dedication you can learn chemistry on your own! Chemistry like all sciences is all about lots of practice!Try the following steps:Find an online tutorial series on chemistry that you like. I would recommend Khan Academy (Chemistry | Khan Academy) or AK lectures on youtube (General Chemistry) or freelance teach on youtube.Listen to the lectures on the topics your book chapter covers. You can go ahead and start from the beginning of your textbook.Read the chapter after you listen to the lectures on that topic.While going through the book, do all of the in-chapter problems, and learn from their explanations. If you still don’t understand how to do that problem, try to google or youtube and find something similar.Do end of the chapter problems and compare your answer with the book’s answers and explanations. (you don’t have to do all of them, but the more practice you do the better)!After each 3 chapters, go back and do some of the problems from all of them to not forget what you have learned.I hope my answer was helpful, and if you have any other questions please visit my website Chemistry Tutor NYC | Transformation Tutoring for more help and answers