1. Define an element?
2. Explain how a compound is formed.
3. What are organic compounds?
4. Explain how polar covalent bonds are formed.
5. Give two examples of the body structures where we can find the hydrogen bonds.
6. Explain the hydrogen bonding.
7. Mention two types of covalent bonding.
8. Define molar volume
9. You have a stock solution of 99% ethanol. Your procedure requires 50 mL solution of 70%
ethanol. Show your working.
i. How much initial volume of the stock solution would you need?
ii. How much volume of distilled water would you add to the initial volume?
iii. How would you prepare the 50ml of 70% ethanol solution needed by dilution?
10. Calculate the volume of carbon dioxide gas, CO2, occupied by 5 moles of the gas at Standard
Temperature and Pressure. Show your working.
11. Calculate the number of moles of ammonia gas, NH3, in a volume of 80 L of the gas measured at
Room Temperature and Pressure. Show your working.
12. With example, define optical isomerism?
13. Define metamerism?
14. Differentiate chain isomerism from functional isomerism
15. In brief explain the IUPAC nomenclature for the naming of branching hydrocarbons structures.
16. Name the compound below.
17. Draw the alkene structure of the molecular formular 2,4-dimethylhept-3-ene.
18. Explain why carbon is able to make large molecules.
1. An element is a substance consisting of atoms that have the same number of protons in their atomic nuclei, such as gold, oxygen, and carbon.
2. A compound is formed when two or more different elements chemically react and bond together to form a new substance with different physical and chemical properties than its constituent elements.
3. Organic compounds are compounds that contain carbon atoms bonded to hydrogen atoms, often found in living organisms and their products, such as sugars, proteins, fats, and DNA.
4. Polar covalent bonds are formed by the unequal sharing of electrons between two atoms with different electronegativities, resulting in a partial positive charge on one atom and a partial negative charge on the other atom.
5. Hydrogen bonds can be found in body structures such as DNA and proteins, where they play important roles in maintaining the structure and function of these molecules.
6. Hydrogen bonding is a type of noncovalent bond that occurs between a hydrogen atom bonded to a highly electronegative atom like oxygen or nitrogen and another electronegative atom in a nearby molecule. This results in an attractive force between the molecules and can contribute to the properties of substances like water.
7. The two types of covalent bonding are polar covalent bonding and nonpolar covalent bonding.
8. Molar volume is the volume occupied by one mole of a substance, typically measured at standard temperature and pressure (STP).
9. i. To make 50 mL of 70% ethanol solution, you would need to calculate the amount of ethanol needed. Let x be the volume of 99% ethanol required, then the amount of ethanol in the final solution is 0.7 * 50 mL = 0.35 * x. Solving for x gives x = 66.67 mL of 99% ethanol.
ii. You would add (50 mL - 66.67 mL) = -16.67 mL or 16.67 mL of distilled water (depending on whether you want to add water first or ethanol first to the container).
iii. To prepare the 50 mL of 70% ethanol solution, you would mix 16.67 mL of distilled water with 66.67 mL of 99% ethanol in a container and stir well.
10. At STP, one mole of any gas occupies 22.4 L of volume. Therefore, 5 moles of CO2 gas would occupy (5 mol) * (22.4 L/mol) = 112 L of volume.
11. At Room Temperature and Pressure (RTP), one mole of any gas occupies 24.5 L of volume. Therefore, 80 L of NH3 gas would contain (80 L) / (24.5 L/mol) = 3.27 moles of NH3 gas.
12. Optical isomerism is a type of stereoisomerism that occurs when a molecule has a chiral center and exists in two non-superimposable mirror-image forms (enantiomers) that have different optical properties, such as the ability to rotate plane-polarized light in opposite directions.
13. Metamerism is a type of structural isomerism that occurs when two or more compounds have the same molecular formula but differ in the arrangement of their alkyl groups attached to a nitrogen or oxygen atom.
14. Chain isomerism occurs when compounds have the same molecular formula but differ in the length or branching of their carbon chains, while functional isomerism occurs when compounds have the same molecular formula but differ in their functional groups or the way they bond.
15. The IUPAC nomenclature for branching hydrocarbon structures involves identifying the longest continuous carbon chain (parent chain) and numbering its carbons to give the substituents (branches) the lowest possible numbers. The branches are named by adding the prefix of the substituent and the suffix "-yl," while the parent chain is named by adding the appropriate prefix and suffix based on the number of carbons in the chain (-ane for alkanes, -ene for alkenes, -yne for alkynes).
16. The compound in the image is ethyl butanoate.
17.
18. Carbon is able to make large molecules due to its ability to form covalent bonds with up to four other atoms, allowing for chains, branches, and rings of carbon atoms to form. Additionally, carbon has a versatile nature that allows it to form double and triple bonds with certain other elements, further expanding its bonding potential and molecular diversity.