The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl) solution. The Kb for methylamine is 4.4 x 10-4. What is the pH of the resulting solution after adding 100 mL of 1.0 M KOH to the original buffer solution?

Iron and oxygen gas react in a combination reaction to form iron(III) oxide. How many moles of iron are needed to make 5.0 moles of iron(III) oxide? Hint: Write and balance the chemical equation.

Multiple Choice

• 2.5 mol

• 10. mol

• 5.0 mol

• 1.0 mol

• 0.50 mol

What is the reduction potential at 25∘C for the hydrogen electrode in each of the following solutions? The half-reaction is as follows:

2H+(aq)+2e−→H2(g,1atm)

Part A 1.0 M HCl.

Part B A solution having pH = 4.16.

Part C Pure water.

Part D 1.1 M NaOH.

. Let Xl' ... ' Xn rv Uniform(0,θ) and let θˆ = max{Xl , ... , Xn}. Find the bias, se, and MSE of this estimator. + If we assume that θˆ is asymptotically normal, what is the 90% percentile confidence interval? Suppose my data was 1.0 2.0 3.0 4.0 5.0 and report some numbers.

For a weak acid, HA,

1) write the ionization reactionin water

2) write the expressio of its acid ionation constant, Ka

3)If Ka is 1.0 x 10^-6, calculate the pH of a 0.200-M Ha solution

4)What is the pH of a buffer solution with 0.35 M HA and 0.40 M A-?

Suppose that the partition coefficient for an amine, B, is K = 3.0 and the acid dissociation constant for BH+ is Ka = 1.0 x 10−9. If 50.0 mL of 0.010 M aqueous amine is extracted with 100.0 mL of solvent two times, what percentage amine remains in aqueous solution if the pH of the aqueous phase is 9.00?

1.0 Name three commonly used management security policy areas and describe an example policy for each area.

2.0 Create an outline for a training session to help your team avoid phishing. What would you include in that training session? What are some typical signs that an e-mail might be fraudulent?

A mole of atoms is 6.02 x 10^23 atoms. To the nearest order of magnitude, how many moles of atoms are in a 8 kg domestic cat? The masses of a hydrogen atom, an oxygen atom, and a carbon atom are 1.0 u, 16 u, and 12 u, respectively. (Hint: Cats are sometimes known to kill a mole.)

A 1.0-cm-tall object is 100 cm from a screen. A diverging lens with focal length -20 cm is 20 cm in front of the object.

a. What is the focal length of a second lens that will produce a well-focused, 2.0-cm-tall image on the screen?

b. What is the distance from the screen of the second lens?

3. THE HOMINID PROGRESSION 7.0 -1.0 MYA (i) The Ape Human transition (ii) The first Hominid candidates (iii) The Rise of the genus Homo (iv) Early Homo Lifestyle (v) Who was Homo erectus? (vi) Is Homo floresiensis a distinct type of hominid and if so where do they fit in the hominid progression?