Search found 13 matches
- Wed Mar 15, 2017 3:04 pm
- Forum: *Alkanes
- Topic: Non-Hydrocarbon Substituants
- Replies: 1
- Views: 634
Non-Hydrocarbon Substituants
How are you supposed IUPEC name hydrocarbons with substituents like bromine and chloride? Is it the number and then just bromo or chloro?
- Wed Mar 15, 2017 3:02 pm
- Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
- Topic: Homework question
- Replies: 2
- Views: 375
Re: Homework question
Why did you think the methyl group had higher priority than the ethyl group? Z (cis) and E (trans) are determined base on the location of the highest priority substituent on either side. To determine priority you look at the atomic number of the molecular attached to the central carbon. In the case ...
- Wed Mar 15, 2017 2:23 pm
- Forum: *Alkanes
- Topic: Naming from Line Structure
- Replies: 2
- Views: 357
Re: Naming from Line Structure
You're right the number in front of the methyl is the number of the carbon it's attached too. How you find that number is that you assign it, making sure that you are using the lowest numbers. Look at this example (a cyclic molecule with two methyl groups you described. http://www.chemspider.com/Ima...
- Wed Mar 15, 2017 2:12 pm
- Forum: *Alkanes
- Topic: 1.16 Ch.1 Organic Textbook Question
- Replies: 2
- Views: 375
Re: 1.16 Ch.1 Organic Textbook Question
The trick is if the prefix is number based you ignore it. Otherwise, it counts for alphabetical.
- Mon Feb 27, 2017 11:27 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Equations for activation energy
- Replies: 1
- Views: 241
Re: Equations for activation energy
The significance of pointing out the difference between the two is it's sometimes useful to have the linear equation. It makes it easy to see how temperature affects the reaction constant K from an equation or a plot. If you were given a plot of the non-linear Arrhenius equation it would be a lot mo...
- Mon Feb 13, 2017 3:36 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Probability of higher order reactions
- Replies: 1
- Views: 372
Re: Probability of higher order reactions
Increasing the temperature and the pressure will increase the kinetic energy of the molecules, which will increase the number of collisions happening over a certain period of time. As the overall number of collisions increases, the number of rare collisions (tetra or trimolecular) will also increase...
- Sun Feb 05, 2017 11:36 pm
- Forum: Balancing Redox Reactions
- Topic: Oxygen Ion Charge
- Replies: 3
- Views: 830
Re: Oxygen Ion Charge
Do you have the rules written out somewhere, because I'm not sure what you're talking about? Oxygen almost always has an oxidation state of -2 (like you would expect from its position in the periodic table and it's electron configuration). There are certain compounds that cause oxygen to have a -1 c...
- Sun Feb 05, 2017 11:28 pm
- Forum: General Science Questions
- Topic: Sig Figs
- Replies: 3
- Views: 583
Re: Sig Figs
If those are the only data points you are given, yes. Otherwise use the least precise measurement not counting measurements that have to be made in whole numbers.
- Sun Feb 05, 2017 11:25 pm
- Forum: Environment, Fossil Fuels, Alternative Fuels
- Topic: Concept of "Cold"
- Replies: 5
- Views: 1330
Re: Concept of "Cold"
First of all, consider the ice the 'system' and the coffee the 'surroundings'. The melting of the ice is an endothermic reaction, it requires heat to occur, so the q of the system increases. According to the first law of thermodynamics, the q of the system = —q of the surroundings, so if the q of th...
- Thu Jan 19, 2017 10:32 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: HW 8.57
- Replies: 2
- Views: 508
Re: HW 8.57
You're overcomplicating it. Hydrogenation just means adding hydrogen, this case adding hydrogen to ethyne to turn it into ethane. It's not telling you that you have to do something to the equation, just naming the reaction occurring (like combustion)
- Thu Jan 19, 2017 10:19 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Help on Problem 8.99 [ENDORSED]
- Replies: 4
- Views: 917
Re: Help on Problem 8.99 [ENDORSED]
The simple answer is that I literally just went to the back of the book to the table of enthalpies and the given enthalpy for Zn was zero. The actual answer goes back to the idea of standard states. If you look on page 17 of the course reader it explains that the standard enthalpy of an element in i...
- Thu Jan 19, 2017 7:49 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Help on Problem 8.99 [ENDORSED]
- Replies: 4
- Views: 917
Re: Help on Problem 8.99 [ENDORSED]
The first thing you need to do is setup the equation so you can calculate the enthalpy of the reaction, which is mixing sold zinc and hydrochloric acid. 2HCl (aq) + Zn (s) --> H 2 (g) + ZnCl 2 or 2H + (aq) + 2Cl - (aq) + Zn (s) --> H 2 (g) + 2Cl - (aq) + Zn 2+ (aq) which simplfies to 2H + (aq) + Zn ...
- Tue Jan 17, 2017 5:35 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess' Law [ENDORSED]
- Replies: 5
- Views: 1544
Hess' Law [ENDORSED]
I don't understand why balancing one of the component equations used when solving Hess's Law you don't have to change the enthalpy. For example, in 8.55, one of the component equations is 2Al(s) + O 2 (g) --> Al 2 O 3 (g) which needs to balanced by multiplying O 2 by two-thirds. Normally when we mak...