Answer:
Explanation: The chemical reaction is written by writing down the chemical formulas of the reactants on the left hand side and the chemical formulas of products on the right hand side separated by a right arrow.
This is a single displacement reaction in which a more reactive element displaces the less reactive element from its salt solution. Thus sodium is more reactive than Mg and thus displaces it from 
.
The number of atoms of each element must be same on both sides of the reaction so as to follow the law of conservation of mass.
Thus the equation is balanced.
Answer:
Two-dimensional structures of methane show that it is a carbon atom bonded to four (4) hydrogen atoms while ethane is two (2) carbon bound to six (6) hydrogens. The three-dimensional structures show that methane is tetrahedral is shape while ethane is trigonal pyramidal. The tw0-dimensional structure does not show bond angles and the position in space of the atoms within the molecule.
Two dimension structure can be used to illustrate a chemical reaction and the exchange of atoms by donors and acceptors in the reaction. Three-dimensional structures are significant in illustrating the crystal lattice of molecules since their 3-D structures determine how the molecules interact with each other
Answer: 1. True 2. False 3. True 4. False
Explanation:
1. True NAD+ is a co-enzyme synthesized from Niacin or Nicotinamide, a member of vitamin B complex. NAD+ is an important cofactor in cellular respiration. In the enzyme catalyzed reaction of Glyceraldehyde-3-P dehydrogenase and lactate dehydrogenase, NAD+ is an important cofactor.
2. False. Cofactor and co-enzymes are not irreversible changed. They are reversible. For example in the 5th step of glycolysis, two molecules of NAD+ are reduced to NADH. The conversion of pyruvate to lactate reconvert NADH to NAD+
3. True . Fe, Zn and Mg are enzyme cofactors. Zinc is a cofactor of alcohol dehydrogenase, carboxyl peptidase. Iron is a cofactor of cytochrome oxidase. Magnesium is a cofactor of Hexokinase.
4. False. Cofactors are optimal, and are not optional. Organisms can not function normally without cofactors.
For example when NAD+ is reduced to NADH in glycolysis the availability of NAD+ in the cell is limited. Therefore the absence of a cofactor becomes a bottleneck in the whole reaction process.
