One of Albert Einstein's contributions to nuclear chemistry was his observation that energy and what are different manifestations of the same thing?
In: Chemistry
The Solvay process involves a reaction of sodium chloride, ammonia and carbon dioxide in aqueous solution. Of the various possible products, the one least soluble in water is?
Select one alternative:
In: Chemistry
how to calculate expected pH , buffer concentration and buffer capacity?
In: Chemistry
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
In: Chemistry
In: Chemistry
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
In: Chemistry
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) 4px b) 6s c) 6dxz d) 5fz3
In: Chemistry
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 ?
In: Chemistry
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.
In: Chemistry
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 .
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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!
In: Chemistry
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?
In: Chemistry
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.
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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.
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