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- Question
Gases used in normal welding?
Options- A. Oxygen and Acetylene
- B. Acetylene and Nitrogen
- C. Oxygen, Hydrogen and Acetylene
- D. Oxygen and Hydrogen
- Correct Answer
- Oxygen and Acetylene
ExplanationNormal Gas welding use oxygen-acetylene.
Depending on what materials you are welding, there are some more options that might be used.
For example - MIG/TIG use Argon, MAG use an argon-something mix.
- 1. What type of bond is joining the two hydrogen atoms?
Options- A. Hydrophobic
- B. Ionic
- C. Covalent
- D. Hydrophilic Discuss
- 2. Tertiary structure is NOT directly dependent on
Options- A. hydrogen bonds
- B. ionic bonds
- C. peptide bonds
- D. hydrophobic interactions Discuss
- 3. Which of the following polysaccharides contains a modified monosaccharide?
Options- A. starch
- B. chitin
- C. glycogen
- D. cellulose Discuss
- 4. Which path through the carbon cycle is possible?
Options- A. Animal ----> Plant ----> Atmosphere
- B. Plant ----> Animal ----> Atmosphere
- C. Atmosphere ----> Plant ----> Animal
- D. Plant ----> Atmosphere -----> Animal Discuss
- 5. Lime is sometimes applied to soil in order to
Options- A. increase the acidity of the soil
- B. make the soil more porous
- C. restore nitrates to the soil
- D. increase the alkalinity of the soil Discuss
- 6. 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
- 7. 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
- 8. Water is an example of?
Options- A. Element
- B. Molecule
- C. Compound
- D. Both B & C Discuss
- 9. 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
- 10. 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
Chemistry problems
Search Results
Correct Answer: Covalent
Explanation:
Covalent type of bonding joins The two hydrogen atoms are joned by Covalent type of bonding.
In this type of bonding, electrons are shared between the atoms in order to fill there valence shells. Thus sharing of electrons take place in between the hydrogen atoms.
Correct Answer: peptide bonds
Correct Answer: chitin
Explanation:
Many carbohydrates contain one or more modified monosaccharide units that have had one or more groups replaced or removed.
Chitin is one of many naturally occurring polymers. It is one of the most abundant natural materials in the world. Over time it is bio-degradable in the natural environment. Its breakdown may be catalyzed by enzymes called chitinases, secreted by microorganisms such as bacteria and fungi, and produced by some plants.
Chitin is composed of repeating units of N-acetylglucosamine, a nitrogen-containing form of glucose.
Correct Answer: Plant ----> Animal ----> Atmosphere
Explanation:
During daylight hours, plants capture carbon dioxide from the atmosphere and use it to make carbohydrates which is stored as starch in the plant. Animals feed on the plants and extract the carbohydrates through their digestive system. The carbohydrates, namely glucose, are used by the animals for production of ATP through cellular respiration.
Cellar respiration in the animals produces carbon dioxide as a waste product. The carbon dioxide is released into the atmosphere, from where it is again captured by plants and the cycle is repeated.
Hence, option B) Plant ----> Animal ----> Atmosphere is the path possible in carbon cycle.
Correct Answer: increase the alkalinity of the soil
Explanation:
Lime is sometimes applied to soil in order to increase the acidity of the soil.
Correct Answer: The sequence of amino acids in the polypeptide chain differs from protein to protein
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: 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: 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: 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.
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