how to calculate expected pH , buffer concentration and buffer capacity?

Chemists often use molarity M, in moles/liter, to measure the concentration of solutions. Molarity is a common unit of concentration because the volume of a liquid is very easy to measure. However, the drawback of using molarity is that volume is a temperature-dependent quantity. As temperature changes, density changes, which affects volume. Volume markings for most laboratory glassware are calibrated for room temperature, about 20?C.

Fortunately, there are several other ways of expressing concentration that do not involve volume and are therefore temperature independent.

A 2.350

Which of the following describes reactions in which two hydrogen atom and one orxgen atom are removed to form water?

a. they link monomers

b. they are called condensation reactions

c. they disaemble polumers

d. they form polymers.

Which of the following correctly described anabolic and catabolic reactions?

a. catabolic reactions use nutrients as fuel

b. Energy released in anabolic reactions can be used to synthesize ATP

c. Anabolic reactions produce ATP

d. An example of a catabolic reaction is converting starch to glucose.

An example of an anabolic reaction is the process of converting excess amino acids into protein for storage as muscle tissue. T or F

What factor is Most closely associated with an increased risk of developing an eating disorder?

a. exposure to media pressure to be thin

b. lack of interest in dieting

c. excess time spent with family

d. concern about having friends

What might predispose a person to developing an eating disorder?

a. a defect in a gene that helps control hunger and satiety

b. a plump female figure is viewed as an ideal body image

c. personality trait where a person feels secure, worthy and capable

d American culture that place much emphasis on intellectual pursuits

Dysorexia thin-fat syndrome and dietary chaos syndrome are terms that can be used to describe

a. binging and purging episodes

b. morbid preoccupation with weight

c. episodic eating patterns regardless of hunger

d. anorexia nervosa

Which of the following might be part of the expected treatment for a person who has been diagnosed with anorexia nervosa?

a. promotion of nutritional rehabilitation that incorporated meal planning

b. limiting dietary choice

c. achievement of ideal body weight in a rapid time frame

d. delay in any treatment until the person is ready psychologically to deal with issues

Dysorexia thin fat syndrome and dietary chaso syndrome are terms that can be used to dsecribe

a. binging and purging episodes

b. morbid preoccupation with weight

c. episodic eating patterns regardless of hunger

d. anorexia nervosa

Draw the following orbitals according to the radial and angular variations of the wavefunction, including phases. Indicate the number of both radial and angular nodes for each orbital. Add axes, if appropriate.

a) 4p_x b) 6s c) 6d_xz d) 5f_z3

Hydrogen gas can be prepared by reaction of zinc metal with aqueous HCl :
Zn(s)+2HCl(aq)→ZnCl2(aq)+H2(g)

1)How many liters of H2 would be formed at 592 mm Hg and 17 ∘C if 25.5 g of zinc was allowed to react?

2)How many grams of zinc would you start with if you wanted to prepare 4.60 L of H2 at 294 mm Hg and 34.5 ∘C ?

The formula for dimethoxyethane (dme) is H3COCH2CH2OCH3 and the formula for

N,N,N',N'-tetramethylethylenediamine (tmeda) is (H3C)2NCH2CH2N(CH3)2.

Tmeda is water-soluble. Is tmeda a strong acid, weak acid, strong base, weak base, or none of these? Briefly justify your choice.

Is dme polar? Justify your choice.

Is tmeda polar? Justify your choice.Is dme more polar, less polar, equally polar, or cannot be determined compared with tmeda? Justify your choice.

Assume that you have 0.480 mol of N2 in a volume of 0.700 L at 300 K .

1)Calculate the pressure in atmospheres using the ideal gas law.

2)Calculate the pressure in atmospheres using the van der Waals equation. For N2 , a=1.35 (L2⋅atm)/mol2 , and b=0.0387 L/mol .        

A magic number is the name given to certain numbers of protons or neutrons that have a high correlation to stability in nuclei:

magic numbers of protons:magic numbers of neutrons:2,8,20,28,50,822,8,20,28,50,82,126,184

A plot of the number of neutrons versus the number of protons for all known stable nuclei, represented by reddish brown dots on the graph, shows that these nuclei cluster together in a region known as the valley of stability. Nuclei with a ratio that is too high tend to undergo beta decay. Nuclei with a ratio that is too low tend to undergo positron emission or electron capture.

Part A

Using general trends, predict the stability of the following nuclei.

Drag the appropriate items to their respective bins, which are Stable and Radioactive

Radium-228, Bromine-82, Sulfur-32,Chlorine-36, Zinc-64

Nuclei with Z≥84 tend to undergo α emission.

Nuclei with high n/p ratios undergo β (  0−1e) emission.

Heavy nuclei with low n/p ratios are more likely to undergo electron (  0−1e) capture.

Light nuclei with low n/p ratios are more likely to undergo positron (01e) emission.

The classification "high" or "low" n/p ratio can be determined by finding the coordinates on the graph that correspond to the number of protons (x or horizontal value) and neutrons (y or vertical value) in a given isotope. Then, observe whether this set of coordinates is above, within, or below the stability valley.
Use this information to solve Part B.

Part B

Using general tendencies and the chart given in the introduction, predict the most likely mode of decay of each of the following radioactive isotopes.

Drag the appropriate items to their respective bins, which are Alpha Decay, Beta Decay, 0/1 e emission, 0/-1 e capture

Iodine-134, Potassium-47,Americium-241,Platinum-183, Fluorine-17

THANK YOU!

perfectly insulated container with no heat capacity is used to mix together the following three samples of water:

I.183.2 grams of water at 23.2 °C

II.32.1 grams of water at 14.2 °C

III.143 grams of water at an unknown temperature.

After the three samples are combined, the final temperature of the combined solutions is 39.0 °C. What is the temperature of sample III before the samples were mixed together?

Select all of the correct statements about reaction rates from the choices below.

A. The lower the rate of a reaction the longer it takes to reach completion.


B. A balanced chemical reaction is necessary to relate the rate of disappearance of a reactant to the rate of appearance of a product.


C. The fastest step in a reaction is called the rate-determining step.


D. The rate of a slow step has more effect on the overall reaction rate than the rate of a fast step.


E. The rate of a reaction is the same as the rate constant of the reaction.


F. Solid catalysts do not affect reaction rates.


G. Reaction rate constants increase with increasing temperature.

The amino acid glutamic acid has the molecular formula C5H9NO4, and the amino acid isoleucine has the molecular formula C6H13NO2. Determine how many moles of isoleucine contain the same number of atoms as 1.96 mol of glutamic acid.

How much ice (in grams) would have to melt to lower the temperature of 354 mL of water from 26 ∘C to 6 ∘C? (Assume the density of water is 1.0 g/mL.)

Piperazine, HN(C4H8)NH, is a diprotic weak base used as a corrosion inhibitor and an insecticide and has the following properties:

pKb1=4.22 pKb2=8.67

For writing the reactions of this base in water, it can be helpful to abbreviate the formula as Pip:

Pip+H2OPipH++H2O??PipH++OH?PipH22++OH?

The piperazine used commercially is a hexahydrate with the formula C4H10N2?6H2O.

a. Calculate the pH after 2.575mL of HCl have been added.

b. Calculate the pH when 12.875mL of HCl has been added.

c. What is the pH at the first midway point?

please don't copy and paste that yahoo answers bs, it doesn't give the right answer.

The corrosion of rebar inside concrete structures is serious issue for the safety and stability of bridges and buildings. The chemistry of corrosion is complex, but a simplified chemical model (iron rusting) is: 4Fe (s) + 3O2 (g) ⟶ 2Fe2O3 (s) ∆H = −1.65 × 103 kJ a) How much heat is released when 1.00 pound of iron rusts? b) If 6.25 × 104 kJ is released, how many kilograms of iron have rusted?