Accounting
Anthropology
Archaeology
Art History
Banking
Biology & Life Science
Business
Business Communication
Business Development
Business Ethics
Business Law
Chemistry
Communication
Computer Science
Counseling
Criminal Law
Curriculum & Instruction
Design
Earth Science
Economic
Education
Engineering
Finance
History & Theory
Humanities
Human Resource
International Business
Investments & Securities
Journalism
Law
Management
Marketing
Medicine
Medicine & Health Science
Nursing
Philosophy
Physic
Psychology
Real Estate
Science
Social Science
Sociology
Special Education
Speech
Visual Arts
Question
An experiment with 55Co takes 47.5 hours. At the end of the experiment, 1.90 ng of 55Co remains. If the half life is 18.0 hours, how many ng of 55Co were originally present?A) 2.47 ng
B) 3.05 ng
C) 3.28 ng
D) 11.8 ng
Answer
This answer is hidden. It contains 1 characters.
Related questions
Q:
In water, which form of glucose predominates?C) open chainD) All three are equal in solution.
Q:
What class of compounds are cyclic?
A) DNA
B) lipids
C) monosaccharides
D) proteins
Q:
Which two amino acids form the dipeptide below? A) asparagine and proline
B) glycine and cysteine
C) serine and alanine
D) threonine and valine
Q:
In the protein, Val-Tyr-His-Pro, which amino acid contains the N-terminal group?
A) histidine
B) proline
C) tyrosine
D) valine
Q:
In addition to an amine, which functional group do all amino acids contain?
A) an alcohol
B) an amide
C) a carboxylic acid
D) an oxyacid
Q:
To which family does this organic compound belong? A) amide
B) amine
C) carboxylic acid
D) ester
Q:
Which are isomers? A) All are isomers.
B) (1) and (2); (3) and (4)
C) (1) and (3); (2) and (4)
D) (1) and (4); (2) and (3)
Q:
What is the IUPAC name of the following alkane? A) decane
B) 2, 4-dimethyloctane
C) 5, 7-dimethyloctane
D) 1, 1, 3-trimethylheptane
Q:
Which of these molecules above have a partial positive charge (δ+) on the carbon atom?
A) only (1)
B) only (3)
C) (1) and (3)
D) (2) and (4)
Q:
What is the H-C-H bond angle?
A) 90
B) 109.5
C) 120
D) 180
Q:
Which one of the following molecules is the most polar?
A) acetaldehyde
B) acetic acid
C) ethane
D) ethylene
Q:
Which one of the following behaves like a base?
A) CH3CONHCH3
B) (CH3)2NH
C) C2H5CONHCH3
D) All of these are bases.
Q:
Which one of the following does not contain a polar carbonyl group?
A) an amine
B) a carboxylic acid
C) an ester
D) a ketone
Q:
Which of the following does not contain a carbonyl group?
A) an alcohol
B) an aldehyde
C) an amide
D) an ester
Q:
What compound is formed by the oxidation of 2-butanol?
A) butanal
B) butanoic acid
C) 2-butanone
D) 2-butene
Q:
The H-C-H bond angles in acetic acid, shown below, are closest toA) 90.B) 109.5.C) 120.D) 180.
Q:
Which compound is not an isomer of the other three?
A) cyclohexane
B) 1, 2-dimethylcyclobutane
C) 1, 2-dimethylcyclopropane
D) methylcyclopentane
Q:
What is the product when pure water and ethene are mixed?
A) an alcohol
B) a carboxylic acid
C) an ether
D) no reaction occurs
Q:
The most important synthetic chemical reactions that alkenes and alkynes undergo are called
A) addition reactions.
B) combustion reactions.
C) photochemical halogenation reactions.
D) substitution reactions.
Q:
The mass defect for the chemical reaction shown below is ________ g.2 F -> F2 E = -159 kJ/mol
Q:
The practical limit for 14C dating occurs when its activity falls to 0.20% of its original value due to interference in detectors by natural background radiation. If the half-life is 5715 years, what is the maximum age of a sample that can be dated by 14C without interference?
A) 1.3 104 years
B) 2.9 104 years
C) 5.1 104 years
D) 2.9 106 years
Q:
Most of the radiation to which people are exposed comes from
A) atmospheric testing of nuclear weapons.
B) emissions from nuclear power plants.
C) medical procedures.
D) natural sources.
Q:
What type of shielding can be used to protect against gamma rays?
A) cloth
B) lead
C) wood
D) No shielding is effective against gamma rays.
Q:
A small block of wood or heavy clothing can form an effective shield against what type of radiation?
A) beta particles
B) cosmic rays
C) gamma rays
D) neutrons
Q:
A rad is:
A) the amount of sample that undergoes 1 disintegration per second.
B) the amount of sample that undergoes 3.7 1010 disintegrations per second.
C) the amount of tissue damage done by radiation.
D) equal to 0.01 J of energy absorbed per kilogram of tissue.
Q:
The first transuranium element was synthesized by bombarding with neutrons. After capturing one neutron, the resulting nuclide was unstable and decayed by beta emission. What was the product of these two nuclear reactions?
A) B) C) D)
Q:
When is formed by bombardment of , what particle(s) was (were) used for the bombardment?C) 4 neutronsD) 2 protons
Q:
Which of these materials has an electrical conductivity that increases with an increase in temperature?
A) materials (1) and (2)
B) materials (1) and (4)
C) materials (2) and (3)
D) materials (3) and (4)
Q:
Which of these materials is a metal?
A) material (1)
B) material (2)
C) material (3)
D) material (4)
Q:
Which of these elements is likely to be extracted from its ore by electrolysis?
A) element A
B) element B
C) element C
D) element D