4 chemistry questions i hope someone can help me answer these 4...?
1.) A 10 L vessel containing 8 g oxygen (O2) is connected by means of a valve to 5 L vessel containing 7 grams of nitrogen (N2) . When the valve was opened and the gases are allowed to mix, what will be the total pressure of the gas mixture at 25 degree celsius assuming temperature was kept constant... 2.) A quantity of 280.7 grams of a hydrate Na2CO3xH20 (please take note of the "x" on the hydrate) was heated in an oven to drive off water. If the steam produced in a 5 L vessel at 110 degree celsius exerted a pressure of 39.6 atm what is the formula of the Hydrate... 3.) The vapor pressure of water at 25 degree celsius is 23.756 torr. a solution consisting of 18.913 grams of non volatile substance in 36 grams water has a vapor pressure of 20.234 torr. What is the molecular weight of the solute. 4.) The half life of strontium 90 is 29 years. What fraction of the atoms in the sample would remain in after "100" years?
Could someone help me with these 5 Chemistry questions?
I really don't like any of these questions or answers. *** 1 b... energy can be defined as the ability to do work. But, from E=mc², energy and mass are equivalent. *** 2 c....chemical energy is energy contained in chemical bonds. However, you can increase the vibrational energy (which would be kinetic) by increasing the temperature of molecules. So the energy in molecular bonds could be kinetic + chemical *** 3.c.. humans are about 62% water by mass. since water is 89% oxygen, .89x62 = 55%.. ie we are about 55% oxygen by mass. *** 4. c, d, e are true.. a is approximately true. b is almost always false let's take each answer by itself... a..the mass of an atom is the sum of the mass of the components + nuclear binding energy/mass.... the mass of a proton = mass of a neutron.. mass of electrons = 1/1822 x mass of a proton. nuclear binding energy < mass of electron. since protons and neutrons and nuclear binding energy are in the nucleus, the majority of the mass of the atom = mass of a nucleus.. but electrons do have mass... b..normally the negatively charge particles, electons, are located outside the nucleus, protons, positively charge particles and neutrons are lockated inside the nucleus. During beta decay, a neutron changes to a proton and ejects an electron or a positron. so for an instant during beta decay, a negative particle can be found in the nucleus. c..particles can be ejected. this occurs during radioactive decay. Beta.. alpha.. etc. d..atomic number = # protons. protons are found in the nucleus. so this is true e..during chemical reactions, electrons interact with other atoms to form chemical bonds. during nuclear reactions, nuclei of different atoms interact. Fusion produces particles that can be absorbed by other atoms, fission is the combination of two nuclei to form a new one *** 5. b. ... isotopes are elements with the same number of protons, ie the same atomic number, but different masses due to different numbers of neutrons. oxygen has atomic number = 8, so anything with atomic number = 8 is an isotope of oxygen
Can somebody help me answer this Chemistry problem?
1.35 x 10^18 m^3 x (100cm/m)^3 = 1.35 x 10^24 cm^31.35 x 10^24 cm^3 x 1 g/cm^3 x 1kg/1000g = 1.35 x 10^21kg
Can someone help me solve these chemistry questions? See question details below.
Leave then blank. Go to the teacher in the morning and explain that you still don't understand and ask them what you could do better to learn. (Remember to go to you biology teacher about this, not your chemistry teacher - you've labelled it you chemistry homework)Asking Quora to help with your homework is not going to help you: in the best case scenario, you've cheated to get slightly better grades. In the worst case scenario, it prevents you from learning effective time-management and prioritization skills and you continue to rely on quora to do your homework nd learn nothing.I'm sure someone will help, but do understand that asking a teacher for help is the right thing to do.
Can someone answer these 10TH GRADE CHEMISTRY questions that have to do with the IDEAL GAS LAW?
1) A gas has a pressure of 655 kPa at 227ºC. What will its pressure be at 27ºC if the volume does not change? 2) a 10 g mass of krypton occupies 15 L at a pressure of 156 kPa. Find the volume of the krypton when the pressure is increased to 215 kPa at the same temperature. 3) A gas occupies a volume of 180 mL at 35ºC and 95.9 kPa. What is the volume of the gas at conditions of STP? 4) A gas has a volume of 550 mL at a temperature of -55ºC. What volume will the gas occupy at 30ºC, assuming constant pressure? Thank you very very much to all who answer...I will make sure to select a best answer
Chemistry help?
could someone answer these few questios for me, i'd appreciate it. 1) Which of the following contains BOTH ionic and covalent bonds? A) CaI2 B) SF6 C) CaSO4 D) COS E) None of the above contain both ionic and covalent bonds. 2) Determine the name for TiCO3. A) titanium (I) carbonate B) titanium (II) carbonite C) titanium carbide D) titanium carbonite E) titanium (II) carbonate
Will someone please help me with these 2 chemistry questions?
I am a junior at Cal Poly, I took 3 Chem classes last year. I do not have my chemistry book with me where I am right now, but I do remember how to answer part A. For this question use the simple formula PV=nRT where P=pressure (in atm. 1 atm=760 torr), V=volume (in Liters), n=number of moles, R is the gas constant (I just looked up the value and it is 0.08206 L atm/mol K), and T = temperature (in Kelvin. Kelvin=degrees C + 273) so to solve for n (number of moles), move the equation around and you get n = PV/RT. substitute the values for P,V,R, and T and solve! don't forget to make sure that all the numbers have been converted to the right units!
Chemistry help!!?
You might want to look again; this is pretty basic stuff. FIRST RULE: In dilution problems, the original number of moles of the solute dont change. The volume of the solvent does. In short moles = [Molar conc] x [volume in L] In problem 1= How much sulfuric acid do you have in MOLES? The answer is .11 L x 3 Molar= 0.33 moles. Now we add 25 ml of water. We have 0.135 L, but still 0.33 moles. So the answer will be 0.33 moles/0.135 L as Molar. In problem 2, we ask again. How much sulfuric acid do you have in MOLES? The answer is 0.05x 18 M = 0.9 moles. Now we add water until the conc. is 0.250 mole/L. At that point, we have a total volume of 0.9 moles/0.250 moles/L. We started with 0.05 L and added the rest. In problem 3, we have to know that for each molecule of sodium phosphate, we have one ion of sodium in solution; the sodium completely ionizes. So we start with how much sodium ion? That's right, 0.1255 L x 3.21 moles/Liter . At the end, we still have that much sodium ion, but the volume is 0.3755 L. You should be able to figure the rest.
What if I put Rs. 500 in my chemistry answer sheet in a board examination?
When I was in class XI, our chemistry teacher was briefing us about the type of question paper that used to come in the board, then all of a sudden she started smiling. When asked about the reason, she decided to tell us as it was our free period (time when the whole syllabus was complete). She told us-“It was way back in 2007, when I was checking the board copies, amongst the whole lot, the next answer sheet that I picked up was light weighted and contained no extra sheets. Initially I was surprised but had a hope that the child must have written that much that she /he scored passing marks .”“I opened the answer sheet and wooo!! Blank sheet, further filled by the lyrics of Nothing's Gonna Change My Love For You and a crisp Rs 500 note giving the excuse that stated “Respected Ma'am/Sir, as I was busy with my sister's wedding I was unable to study for the exam, I request you to kindly grant me passing marks” and I was rolling on the floor laughing!”Then what?The whole group of teachers ordered samosas and chai and needless to say, the child failed.
(chemistry)can someone help me with these three problems?(In full detail) Thanks for your assistance..?
To answer addition and subtraction problems using scientific notation is very easy. Just convert one (or the other, it don't matter which one) so that both numbers have the same exponent. Then line up the decimal point and perform the mathematical operation. I do the first one for you, you do the rest: 7.61 x 10^2 = 0.761 x 10^3. Then just subtract: 8.50 - 0.761 = 7.739 x 10 ^3 (just carry the 10^3 down to the answer, as both of them are 10^3). If you require using significant figures, and you should, the first number (8.50) has 3 sig no., which the second number (7.61 also has 3 sig no, so your answer should only have 3 sig figures, thus the correct "significant" answer can only have 3 sig no., thus the answer would be 7.74 x 10^3 Note: re sig fig; if the two (or more) numbers have different sig figures in them, always pick the one with the LOWEST number of sig figures, and put your answer using that lowest number of sig figures.