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Question
Among the main-group elements the number of semimetals is ________.A) five
B) six
C) seven
D) eight
Answer
This answer is hidden. It contains 1 characters.
Related questions
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What is the IUPAC name of the following alkane? A) decane
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Which of these molecules above have a partial positive charge (δ+) on the carbon atom?
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What is the H-C-H bond angle?
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Which one of the following molecules is the most polar?
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B) acetic acid
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Which one of the following behaves like a base?
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C) C2H5CONHCH3
D) All of these are bases.
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Which one of the following does not contain a polar carbonyl group?
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What compound is formed by the oxidation of 2-butanol?
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C) 2-butanone
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Q:
The H-C-H bond angles in acetic acid, shown below, are closest toA) 90.B) 109.5.C) 120.D) 180.
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Which compound is not an isomer of the other three?
A) cyclohexane
B) 1, 2-dimethylcyclobutane
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D) methylcyclopentane
Q:
What is the product when pure water and ethene are mixed?
A) an alcohol
B) a carboxylic acid
C) an ether
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Q:
The most important synthetic chemical reactions that alkenes and alkynes undergo are called
A) addition reactions.
B) combustion reactions.
C) photochemical halogenation reactions.
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The mass defect for the chemical reaction shown below is ________ g.2 F -> F2 E = -159 kJ/mol
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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?
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A) atmospheric testing of nuclear weapons.
B) emissions from nuclear power plants.
C) medical procedures.
D) natural sources.
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What type of shielding can be used to protect against gamma rays?
A) cloth
B) lead
C) wood
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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
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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.
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When is formed by bombardment of , what particle(s) was (were) used for the bombardment?C) 4 neutronsD) 2 protons
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Which of these materials is a metal?
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B) material (2)
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Q:
Which of these elements is likely to be extracted from its ore by electrolysis?
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B) element B
C) element C
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