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- Question
Which of the following is not a semiconductor?
Options- A. CdS
- B. NaCl
- C. Si
- D. Ge
- Correct Answer
- NaCl
ExplanationSemiconductors are those materials that are neither good conductors nor the good insulators of heat and electricity. Silicon (Si), Germanium (Ge) and Cadmium Sulphide (CdS) are semiconductors which work as conductors in some special conditions only.
- 1. Which formula represents a polar molecule?
Options- A. C - O
- B. C - N
- C. H - N
- D. All of the above Discuss
- 2. Carbon disulfide is prepared by heating sulfur and charcoal.
Options- A. TRUE
- B. FALSE Discuss
- 3. Which process is a chemical change?
Options- A. Burning gasoline
- B. Boiling water
- C. Evaporating water
- D. Melting ice Discuss
- 4. Monazite is an ore of
Options- A. Platinum
- B. Radium
- C. Uranium
- D. Lanthanum Discuss
- 5. In which of the following activities silicon carbide is used
Options- A. Disinfecting water of ponds
- B. Making casts for statues
- C. Making cement and glass
- D. Cutting very hard substances Discuss
- 6. Radioactive decay is likely to occur when
Options- A. an atom has too many neutrons or protons
- B. protons break into neutrons and electrons
- C. an atom has too many electrons
- D. atoms collide with one another Discuss
- 7. The compound MgCl2 is named
Options- A. Magnesium Chloride
- B. Magnesium Chlorine
- C. Magnesium Dichloride
- D. Dimagnesium Chloride Discuss
- 8. Barbituric Acid was synthesized in 1864 by
Options- A. Adolf von Baeyer
- B. Marie Curie
- C. Mendeleev
- D. John Dalton Discuss
- 9. The first two steps in the lithification process are
Options- A. Cementation and Proposal
- B. Compaction and Ratification
- C. Compaction and Cementation
- D. Ratification and Cementation Discuss
- 10. Which has the lowest freezing point?
Options- A. Mercury
- B. Helium
- C. Cesium
- D. Aluminium Discuss
Chemistry problems
Search Results
Correct Answer: All of the above
Explanation:
A chemical bond in which the electrons are not shared equally due to differences in the electronegativity of the atoms.
The polarity of a covalent bond is measured using its dipole moment.
? Large dipole moment = more polar
? Small dipole moment = more nonpolar.
Correct Answer: TRUE
Explanation:
Yes, Carbon disulfide is prepared by heating sulfur and charcoal.
S2 + C ----> CS2
Correct Answer: Burning gasoline
Explanation:
Burning gasoline is the only process that involving in a chemical change in the given options. A chemical change is a change in the starting substances that are called reactants from the formed new substances that are called products.
Correct Answer: Lanthanum
Explanation:
Monazite is an ore of cerium, thorium and lanthanum.
Correct Answer: Cutting very hard substances
Correct Answer: an atom has too many neutrons or protons
Explanation:
Radioactive decay is likely to occur when the nuclei of an atom doesn't have enough binding energy to hold the nucleus together due to excess of rotons or nutrons in it.
Correct Answer: Magnesium Chloride
Explanation:
The compound MgCl2 is named as Magnesium Chloride.
Correct Answer: Adolf von Baeyer
Explanation:
German Chemist, Adolf von Baeyer first synthesized Barbituric Acid in 1864.
Correct Answer: Compaction and Cementation
Explanation:
The first two steps in the lithification process are Compaction and Cementation.
Correct Answer: Helium
Explanation:
Helium has the lowest freezing point of all the elements. When coming to metals, mercury has the lowest freezing point of all the metals.
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