A sample has a Subscript 6 Superscript 14 Baseline Upper C activity of 0.0020 Bq per gram of carbon. (a) Find the age of the sample, assuming that the activity per gram of carbon in a living organism has been constant at a value of 0.23 Bq. (b) Evidence suggests that the value of 0.23 Bq might have been as much as 37% larger. Repeat part (a), taking into account this 37% increase.

13# A 29.3 g of a new element was isolated from 660 kg of the ore molybdenite. The percent by mass of this element in the ore molybdenite was:

A) 44%

B)6.6%

C)29.3%

D) 0.0044%

E)19.3%

14# SO2 reacts with H2S as follows:

2H2S + SO2----3S + 2H2O

When 7.50g of H2S reacts with 12.75 g of SO2, which statement applies?

A) 6.38g of sulfur are formed

B) 10.6g of sulfur are formed

C)0.0216 moles of H2S remain

D) 1.13g of H2S remain

E) SO2 is the limiting reagent

15# Roundup,an herbicide manufactured by Monsanto, has the formula C3H8NO5P. How many moles are there in a 295.1-g sample of roundup?

18# You mix 55ml of 1.00 M silver nitrate with 25Ml of 0.84M sodium choride. What mass of silver choride should you form ?

Both starch and cellulose are polymers of glucose. Why is one, starch, readily digestible by a variety of organisms, including humans and the other digestible by a limited number of organisms? What prevents cellulose from being digested by most organisms? Locate another polymer that exhibits similar properties, and describe it here.

A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur.

Solution A: 3.61{\rm \\%} (m/v) NaCl

Solution B: 4.16{\rm \\%} (m/v) glucose

Solution C: distilled H2O

Solution D: 7.79{\rm \\%} (m/v) glucose

Solution E: 5.0% (m/v) glucose and 0.9% (m/v) NaCl

Drag each solution to the appropriate bin.

How many grams of Na3PO4 must be added to 1.0 L of 0.20 M Na2HPO4 to produce a buffer solution with pH = 11.7?

Butane, C4H10, reacts with oxygen, O2, to form water, H2O, and carbon dioxide, CO2, as shown in the following chemical equation:

2C4H10(g)+13O2(g)→10H2O(g)+8CO2(g)

a) Calculate the mass of water produced when 2.04 g of butane reacts with excess oxygen.

b) Calculate the mass of butane needed to produce 72.8 g of carbon dioxide.

I can't get this question. It doesn't make any sense.

In Elmo’s world, the study of chemistry is just beginning. It is a much simpler world with only a few elements. The Journal of the Elmo Chemical Society reports the following compounds have been created: Q₂E; QP; WX; WP₂; Z₂D; AV; and SX. Elmo has been unable to make any compounds with element T or with element G. Elmo has also determined the atomic masses of all the known elements.

Elmo and his friends now need your help in building a Periodic Table and suggesting new areas of research.

First, consider the data on atomic masses and on the compounds which have been made. (Since they are just beginning, some elements may not have been discovered yet.) Make a Periodic Table for Elmo’s world. Leave gaps where necessary for elements which are not yet discovered.

Second, explain to Elmo how the table you made is arranged.

Third, suggest the formula for compounds made from A and X, from S and E, from A and P, and from B and Z.

A hydrocarbon with general formula CxHy was burned completely in air, yielding .18g of water and .44 g of carbon dioxide. Which formula could give such data? Please explain step by step process. The answer is C2H4 and molar mass for water is 18. g/mol-1 and CO2 is 44.0 g / mol -1

2- Calculate the pH and fraction of dissociation of a 0.00753 M sodium hypochlorite solution (NaOCl) solution.

Determine the oxidation number of P in H3PO3, Mn in KMnO4, Mn in MnO2, N in Ca(NO3)2, O in H2O2.

Balance the following equation. Show each half-reaction and the final, overall reaction. Label the oxidizing agent, the reducing agent, the species that is oxidized and the species that is educed.

Fe2+ + Cr2O7 2- → Fe3+ + Cr3+ (acidic solution)

An octapeptide with the amino acids < Ile, Arg, Met, Phe, Pro, Thr, Tyr, Val > was subjected to digestion reactions A, B and C in order to deduce its amino acid sequence. The following results were obtained. The exact position occupied by each of the amino acids (positions 1-8 in the sequence) will be known when the results are analyzed

A. Digestion with Trypsin yielded a [Thr-Arg] dipeptide and a [hexapeptide] with the remaining amino acids.

Question (A1): Explain the reasoning for the fragmentation pattern
Question (A2): What can you deduce regarding the exact positions occupied by Thr and Arg in the

sequence?

B. Cyanogen bromide treatment of the octapeptide also yielded a dipeptide [Phe-Pro] and a hexapeptide. Question (B1): Explain the reasoning for the above fragmentation pattern

Question (B2): What can you deduce regarding the exact positions occupied by Phe and Pro in the sequence?

C. Chymotrypsin cleaved the octapeptide into two tetrapeptides, one with and the other

Question (C1): Explain the reasoning for the above pattern
Question (C2): What can you deduce regarding the exact positions occupied by Val and Ile in the

sequence?

Question (D): What is the sequence of the peptide?

How many moles of PCl5 can be produced from 28.0 g of P4 (and excess Cl2)?

Using MO diagram, explain why cycloctatetraene is very reactive.