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- Question
Oxidation number of S8 ?
Options- A. +1
- B. -2
- C. +2
- D. 0
- Correct Answer
- 0
Explanationis an elemental form of sufur. In elemental form it can't be reduced or oxidized. Hence, it oxidation number is zero and thus sulfur is zerovalent here.
- 1. Atoms have no electric charge because they
Options- A. have same number of electrons and neutrons
- B. have same number of electrons and protons
- C. have same number of protons and neutrons
- D. have same number of protons, electrons and neutrons Discuss
- 2. Is deposition endothermic or exothermic?
Options- A. Endothermic
- B. Exothermic
- C. Both A & B
- D. Can't be determined Discuss
- 3. Identify the metalloid in the following list?
Options- A. Silicon
- B. Sulphur
- C. Scandium
- D. All of the above Discuss
- 4. Compounds are formed as a result of chemica change.
Options- A. TRUE
- B. FALSE Discuss
- 5. The mass of a mole of NaCl is the
Options- A. 58.44 gm/mol
- B. 57.25 gm/mol
- C. 56.31 gm/mol
- D. 59.14 gm/mol Discuss
- 6. Which statement describes the acid found in vinegar acetic acid ?
Options- A. It feels slippery
- B. It reacts with Mg to produce H2
- C. It tastes bitter
- D. It releases OH- in a solution Discuss
- 7. What is the name for the compound P4O10 ?
Options- A. Phospholipid
- B. Phosphoric acid
- C. Phosphorus pentoxide
- D. Phosphorus decoxide Discuss
- 8. Which is a pair of allotropes?
Options- A. carbon-16 and carbon-12
- B. diamond and graphite
- C. carbon dioxide and graphite
- D. diamond and carbon dioxide Discuss
- 9. Which of the following is a hydrocarbon?
Options- A. C2H6
- B. C3H8
- C. CH4
- D. All of the above Discuss
- 10. Which statement describes nuclear binding energy?
Options- A. It is the energy that is required to overcome mass defect.
- B. It is the result of converting mass to energy.
- C. It is the energy that is required to bind protons and neutrons together in a nucleus.
- D. None of the above Discuss
Chemistry problems
Search Results
Correct Answer: have same number of electrons and protons
Explanation:
Atoms are composed of three main particles called electrons, protons and neutrons. We know that, the electrons are negatively charged particles whereas protons are positively charged and neutrons have no charge.
Hence, as the number of electrons and protons are equal and they are oppositely charged, the atom will have no charge as their charges cancel each other.
Correct Answer: Exothermic
Explanation:
In thermodynamics, deposition is a phase transition in which gases are directly transformed to solids without converting to liquids first.
For example, watervapour is directly changed to ice without first becoming to liquid water. In this process, heat is released making the process exothermic process.
Correct Answer: Silicon
Explanation:
A metalloid is an element with properties between metals and non metals or the mix of both.
The six metalloids are arsenic, silicon, germanium, boron, antimony and tellurium.
Hence, silicon is the only metalloid in the given list.
Correct Answer: TRUE
Explanation:
TRUE, the compounds are formed as a result of chemical change.
Correct Answer: 58.44 gm/mol
Explanation:
To get the mass of a mole of NaCl, we need to add the molar atomic weights of the individual elements i.e, Na and Cl
Atomic weights of Na = 22.99 gm/mol Cl = 35.45 gm/mol
Now, mass of a mole of NaCl = 22.99 + 35.45 = 58.44 gm/mol.
Correct Answer: It reacts with Mg to produce H2
Explanation:
Acid which is present in vinegar is approximately 5 % of acetic acid. This can be confirmed by testing the vinegar with magnesium which gives out hydrogen as a gas.
Correct Answer: Phosphorus pentoxide
Explanation:
The compound with the molecular formula is called Phosphorus pentoxide or tetraphosphorous decoxide. It is an anhydride of the Phosphoric acid.
Correct Answer: diamond and graphite
Explanation:
Allotropes are the different physical forms of an element. Here in the given options, diamond and graphite are the pair of allotropes of carbon.
Some more examples are Molecular oxygen and ozone are pair of allotropes, Black and red phosphorous are also pairs of allotropes.
Correct Answer: All of the above
Explanation:
The simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons.
Here all the given options are hydrocarbons.
Correct Answer: It is the energy that is required to overcome mass defect.
Explanation:
Nuclear binding energy is the minimum energy that would be required to disassemble the nucleus of an atom into its component parts. These component parts are neutrons and protons, which are collectively called nucleons.
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