Search found 30 matches

by alexis castro 1B
Tue Aug 01, 2017 8:48 pm
Forum: *Titrations & Titration Calculations
Topic: 13.29
Replies: 1
Views: 577

13.29

Suppose that 1.436 g of impure sodium hydroxide is dissolved in 300. mL of aqueous solution and that 25.00 mL of this solution is titrated to the stoichiometric point with 34.20 mL of 0.0695 m HCl(aq). What is the percentage purity of the original sample? Was anyone able to figure out this problem? ...
by alexis castro 1B
Sun Jul 30, 2017 12:59 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: 13.11
Replies: 1
Views: 510

13.11

A buffer solution of volume 100.0 mL is 0.100 m CH3COOH(aq) and 0.100 m NaCH3CO2(aq). (a) What are the pH and the pH change resulting from the addition of 10.0 mL of 0.950 m NaOH(aq) to the buffer solution? (b) What are the pH and the pH change resulting from the addition of 20.0 mL of 0.100 m HNO3(...
by alexis castro 1B
Fri Jul 28, 2017 6:58 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: homework 12.63
Replies: 1
Views: 220

homework 12.63

The percentage deprotonation of benzoic acid in a 0.110 m solution is 2.4%. What is the pH of the solution and the Ka of benzoic acid?

Can someone tell me how they solved this? I am confused about what the solutions manual is doing.
by alexis castro 1B
Thu Jul 27, 2017 7:26 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: homework 12.39
Replies: 1
Views: 290

homework 12.39

Using data in Tables 12.1 and 12.2, place the following acids in order of increasing strength: HNO2, HClO2, NH3OH, (CH3)2NH2.

Im confused because (CH3)2NH2 isn't given in the tables so how would I find the Ka for it?
by alexis castro 1B
Wed Jul 26, 2017 9:36 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: homework 12.25
Replies: 1
Views: 656

homework 12.25

Calculate the initial molarity of Ba(OH)2 and the molarities of Ba2, OH, and H3O in an aqueous solution that contains 0.43 g of Ba(OH)2 in 0.100 L of solution.

Can someone tell me how i would set this problem up? i thought i would use ICE box but I am not sure.
by alexis castro 1B
Sat Jul 22, 2017 9:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure and Volume
Replies: 4
Views: 341

Re: Pressure and Volume

604744616 wrote:Does anyone know if any of the end of the section for the chemical equilibrium will be put on the test? I want to know how much of this section of chemical equilibrium will be covered?


all of chapter 11 can be asked about on the test.
by alexis castro 1B
Sat Jul 22, 2017 12:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 11.49
Replies: 1
Views: 178

Homework 11.49

I was wondering if we are able to put solids and liquids into an ICE chart. For question 49 the reactant side is only Solids so do i include this in the ICE chart?
by alexis castro 1B
Fri Jul 21, 2017 6:43 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure and Volume
Replies: 4
Views: 341

Pressure and Volume

Can someone please explain the relation between pressure and volume for chemical equilibrium reactions. I got a little lost in lecture.
by alexis castro 1B
Thu Jul 20, 2017 7:53 pm
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 2
Views: 301

Re: Lewis Structure

for that example because NH2 is in parenthesis next to the C in H2C you can tell that they are saying that the nitrogen will be connected to this carbon.
by alexis castro 1B
Tue Jul 18, 2017 9:18 pm
Forum: Dipole Moments
Topic: Exam 1 question 5E
Replies: 1
Views: 213

Exam 1 question 5E

What -1 anion is isoelectronic with Mg2+? can someone tell me the answer and explain why it is the answer.
by alexis castro 1B
Sun Jul 16, 2017 8:03 pm
Forum: Formal Charge and Oxidation Numbers
Topic: What does the formal charge tell us?
Replies: 3
Views: 476

Re: What does the formal charge tell us?

Yes when you get a charge of +1 an electron has been lost but most important formal charge tells us which lewis structure is the most stable.
by alexis castro 1B
Thu Jul 13, 2017 10:38 pm
Forum: Student Social/Study Group
Topic: Lewis Structure Module?
Replies: 3
Views: 378

Re: Lewis Structure Module?

There are no modules for lewis structures.
by alexis castro 1B
Thu Jul 13, 2017 6:54 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable
Replies: 1
Views: 1241

Polarizable

Can someone explain what makes an element highly polarizable and the what makes other elements not polarizable. I am having a hard time grasping this concept.
by alexis castro 1B
Tue Jul 11, 2017 8:06 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Hw #2.25
Replies: 2
Views: 336

Re: Hw #2.25

4P orbitals: n=4 l=1 ml= -1,0,1 so that means the p orbital has 3 orbitals and each orbital can hold 2 electrons so for the 4P orbital it can have 6 electrons 3D n= 3 l=2 ml= -2, -1, 0, 1, 2 so 5 orbitals each holding 2 electron means a total of 10 electrons 1s n=1 l=0 ml=0 so 1 orbital only 2 elect...
by alexis castro 1B
Tue Jul 11, 2017 7:05 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Chapter 2, Question 31
Replies: 1
Views: 282

Re: Chapter 2, Question 31

Because n=6 l is able to equal 0, 1, 2, 3, 4, and 5. l in this case equals 3 which refers to f orbital. Theoretically this is a possible orbital but it is just not the ground state of any element on the periodic table.
by alexis castro 1B
Tue Jul 11, 2017 7:02 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.17 [ENDORSED]
Replies: 6
Views: 683

G.17 [ENDORSED]

(b) Determine the mass of CuSO45H2O that must be used to prepare 250 mL of 0.20 m CuSO4(aq). Can someone tell me the steps they took to solve this problem?
by alexis castro 1B
Sat Jul 08, 2017 3:05 pm
Forum: Bond Lengths & Energies
Topic: ionization energy
Replies: 2
Views: 310

ionization energy

Which has the smaller first ionization energy Al or Na. What is a FIRST ionization energy? is it asking for like the original ionization energy before either of these elements start losing or gaining electrons?
by alexis castro 1B
Fri Jul 07, 2017 9:49 pm
Forum: Formal Charge and Oxidation Numbers
Topic: homework 3.23
Replies: 4
Views: 401

homework 3.23

Chlorine can exist in both positive and negative oxidation states. What is the maximum (a) positive and (b) negative oxidation number that chlorine can have?

Can someone explain what a positive and negative oxidation state is?
by alexis castro 1B
Thu Jul 06, 2017 10:07 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Chapter 2 Homework Number 2.27
Replies: 1
Views: 242

Re: Chapter 2 Homework Number 2.27

To figure this out you must know what each number of l stands for.
for example:
L=0 its an S orbital
L=1 its a P orbital
L=2 its a D orbital
L=3 its a F orbital

so for n=5 and l=2 it would be 5D
by alexis castro 1B
Thu Jul 06, 2017 10:04 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg's Equation [ENDORSED]
Replies: 2
Views: 321

Re: Rydberg's Equation [ENDORSED]

What Lavelle has taught us in class is the empirical version of the Rydberg equation. You can still use the equation lavelle showed us in class to solve the problem but it would just take a few more steps than how the solutions manual showed it with just plugging it all into the original version of ...
by alexis castro 1B
Wed Jul 05, 2017 6:46 pm
Forum: Limiting Reactant Calculations
Topic: Exercise M.11 - Part (c)
Replies: 1
Views: 2713

Re: Exercise M.11 - Part (c)

It is referring to the excess amount of reactant in the second reaction.
by alexis castro 1B
Sun Jul 02, 2017 6:34 pm
Forum: Empirical & Molecular Formulas
Topic: Self Test 1 #5
Replies: 4
Views: 419

Re: Self Test 1 #5

Or is oxygen not in the compound?
by alexis castro 1B
Sun Jul 02, 2017 6:33 pm
Forum: Empirical & Molecular Formulas
Topic: Self Test 1 #5
Replies: 4
Views: 419

Re: Self Test 1 #5

I got 1 for C and 4 for H also but what I was confused about is the oxygen. I got 4 for Oxygen but it doesn't seem right.
by alexis castro 1B
Sun Jul 02, 2017 1:17 pm
Forum: Empirical & Molecular Formulas
Topic: Self Test 1 #5
Replies: 4
Views: 419

Self Test 1 #5

6.40g of a compound was burned in air and produced 8.80g CO2 and 7.2g of H2O. find the empirical formula of the compound.

Can someone please help. I am so lost on this question.
by alexis castro 1B
Fri Jun 30, 2017 10:13 pm
Forum: Empirical & Molecular Formulas
Topic: Whole Number Coefficients
Replies: 5
Views: 469

Re: Whole Number Coefficients

Ya it is pretty much guess and check but my TA said you shouldn't be multiplying by anything bigger than 4 or 5
by alexis castro 1B
Fri Jun 30, 2017 10:09 pm
Forum: SI Units, Unit Conversions
Topic: Practice Tests?
Replies: 2
Views: 477

Re: Practice Tests?

you can try and see if SAC has any old test in their test bank
by alexis castro 1B
Fri Jun 30, 2017 8:20 pm
Forum: Student Social/Study Group
Topic: Exams/tests ?
Replies: 4
Views: 439

Re: Exams/tests ?

I have heard they are more math based but if you have the course reader it has past exams and test in there so you can get a feel for how his test will be set up.
by alexis castro 1B
Thu Jun 29, 2017 7:45 pm
Forum: SI Units, Unit Conversions
Topic: Avogadro's number
Replies: 2
Views: 454

Avogadro's number

Can someone explain, in a more simple way than what the book did, how Avogadro found the number 6.022x10^23 and knew it was universal and could be applied to any element to convert it from moles to molecules.
by alexis castro 1B
Wed Jun 28, 2017 7:05 pm
Forum: Limiting Reactant Calculations
Topic: Question on limiting reactant calculations
Replies: 2
Views: 275

Re: Question on limiting reactant calculations

No. because if one side is greater than the other side of the equation then mass is being created or destroyed which is not possible.
by alexis castro 1B
Tue Jun 27, 2017 11:20 pm
Forum: Molarity, Solutions, Dilutions
Topic: homework G5
Replies: 6
Views: 520

homework G5

2.15 mmol Na+. what does mmol stand for/ mean?

Go to advanced search