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- Question
Iron rusting, chemical or physical change
Options- A. Chemical
- B. Physical
- C. Both A & B
- D. None of the above
- Correct Answer
- Chemical
ExplanationIn rusting the Iron ore make a chemical reaction with the oxygen in the presence of water and environmental or atmospheric moisture to produce an Iron oxide. Iron oxide is otherwise called as rust.
The rusting of iron is a chemical change because it is two substances reacting together to make a new substance. - 1. Which statement is true of all atoms that are anions?
Options- A. The atom has fewer protons than does a neutral atom of the same element.
- B. The atom has more protons than electrons.
- C. The atom has more neutrons than protons.
- D. The atom has more electrons than protons. Discuss
- 2. The reactivity of an atom arises from
Options- A. the existence of unpaired electrons in the valence shell
- B. the energy differences between the electron shells
- C. the sum of the potential energies of all the electron shells
- D. the average distance of the outermost electron shell from the nucleus Discuss
- 3. Water is an example of?
Options- A. Element
- B. Molecule
- C. Compound
- D. Both B & C Discuss
- 4. Which of the following vitamins are water soluble?
Options- A. Vitamins B & C
- B. Vitamins K, D & C
- C. Vitamins A, D & K
- D. Vitamins A, K, B, C & D Discuss
- 5. Proteins differ from one another because
Options- A. The peptide bonds linking amino acids differ from protein to protein
- B. Each protein contains its own unique sequence of sugar molecules
- C. The number of nucleotides found in each protein varies from molecule to molecule
- D. The sequence of amino acids in the polypeptide chain differs from protein to protein Discuss
- 6. Chemical name of Gold?
Options- A. Argentinum
- B. Ferrus
- C. Aurum
- D. Selenium Discuss
- 7. What is a product in a chemical reaction? Discuss
- 8. Which of the following is a micro nutrient?
Options- A. Mg
- B. Cl
- C. P
- D. Ca Discuss
- 9. What does the Aufbau Principle state
Options- A. Electrons will be added to an atom starting from the lowest possible level or sublevel.
- B. Electrons will be added to an atom only if the orbitals are different colors.
- C. Electrons will be added to an atom in a random order.
- D. Electrons will be added to an atom in a symmetrical manner. Discuss
- 10. What is the conjugate base of H2O?
Options- A. NH3+
- B. OH-
- C. H2O
- D. All the above Discuss
Chemistry problems
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Correct Answer: The atom has more electrons than protons.
Explanation:
Anions are atoms or radicals (groups of atoms), that have gained electrons. Since they now have more electrons than protons, anions have a negative charge.
Correct Answer: the existence of unpaired electrons in the valence shell
Explanation:
When atoms react they do so in order to reach the lowest energy, which is the most stable. The electrons orbitals will overlap in the way that reduces the energy the most. Orbitals of similar energy will produce the greatest stabilisation.The answer you gave isn't the whole story, it depends what species is reacting with what. The effective nuclear charge on the atom will affect the energy of the valance electrons.
Hence, the reactivity of an atom arises from the existence of unpaired electrons in the valence shell.
Correct Answer: Both B & C
Explanation:
Why Water Is Not an Element :
An element is a substance consisting of only one type of atom. Water consists of two types of atoms: hydrogen and oxygen.
water is both a molecule and a compound :
A compound forms whenever two or more atoms form chemical bonds with each other. The chemical formula for water is H2O, which means each molecule of water consists of one oxygen atom chemically bonded to two hydrogen atoms.
Thus, water is a compound.
It's also a molecule, which is any chemical species formed by two or more atoms chemically bonded to each other. The terms molecule and compound mean the same thing and can be used interchangeably.
Hence, water is both a molecule and a compound.
Correct Answer: Vitamins B & C
Explanation:
Vitamins are essential nutrients found in foods. They perform specific and vital functions in a variety of body systems, and are crucial for maintaining optimal health.
The two different types of vitamins are fat-soluble vitamins and water-soluble vitamins.
Fat-soluble vitamins :
Vitamins A, D, E and K ? dissolve in fat before they are absorbed in the bloodstream to carry out their functions. Excesses of these vitamins are stored in the liver, and are not needed every day in the diet.
Water-soluble vitamins :
Vitamins dissolve in water and are not stored by the body. Since they are eliminated in urine, we require a continuous daily supply in our diet. The water-soluble vitamins include the vitamin B-complex group and vitamin C.
Water-soluble vitamins are easily destroyed or washed out during food storage or preparation.
Correct Answer: The sequence of amino acids in the polypeptide chain differs from protein to protein
Correct Answer: Aurum
Explanation:
The Chemical name of Gold is Aurum with symbol Au with atomic number 79 and a group 11 element. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal.
Chemically, gold is a transition metal.
Correct Answer: In chemistry, a product is a substance that is formed as the result of a chemical reaction In a reaction, starting materials called reactants and the ending materials are called products
Correct Answer: Cl
Explanation:
The micronutrients (or trace minerals): boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo), nickel (Ni). and cobalt (Co).
Correct Answer: Electrons will be added to an atom starting from the lowest possible level or sublevel.
Explanation:
The Aufbau Principle states that in the ground state of an atom, an electron enters the orbital with lowest energy first and subsequent electrons are fed in the order of increasing energies.
Correct Answer: OH-
Explanation:
A conjugate acid, is a species formed by the reception of a proton (H+) by a base?in other words, it is a base with a hydrogen ion added to it.
On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the removal of a proton from an acid.
Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic.
Represented as the following chemical reaction:
Acid + Base ? Conjugate Base + Conjugate Acid
The water molecule is the conjugate acid of the hydroxide ion after the latter received the hydrogen proton donated by ammonium. On the other hand, ammonia is the conjugate base for the acid ammonium after ammonium has donated a hydrogen ion towards the production of the water molecule. We can also refer to OH- as a conjugate base of H2O, since the water molecule donates a proton towards the production of NH+4 in the reverse reaction, which is the predominating process in nature due to the strength of the base NH3 over the hydroxide ion.
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