Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
38 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
What does a hydrocarbon contain? |
Hydrogen and carbon only |
|
|
|
What is cracking? |
Splitting large molecules into smaller ones to meet the demand for other hydrocarbons |
|
|
|
How is crude oil separated? |
By fractional distillation |
|
|
|
What does crude oil contain? |
Hydrocarbons |
|
|
|
What are the fractions from a fractionating column in order from hottest to coldest? |
Bitumen Oil Diesel Paraffin/kerosene Naphtha Petrol LPG |
|
|
|
Which fractions have the highest boiling points (top or bottom)? |
Bottom of the column |
|
|
|
How does fractional distillation work? distillation work? |
Long hydrocarbon chains (crude oil) is heated until it is turned into a gas which is released into the fractional distillation column. The column is hot at the bottom and colder at the top. The hydrocarbons condense in the column depending on their boiling and melting point. The condensed hydrocarbon then collects on a tray and is piped out of the column. |
|
|
|
What is crude oil? |
A compound of different molecules |
|
|
|
What type of chemical reaction is cracking? |
Thermal decomposition |
|
|
|
What is the trend for hydrocarbons boiling points in terms of intermolecular forces? |
The larger the hydrocarbon chain, the stronger the intermolecular forces and the higher the boiling point. |
|
|
|
How are the atoms in hydrocarbon molecules joined together? |
By covalent bonds |
|
|
|
What happens to a hydrocarbon molecule as the size increases? |
The boiling point increases, its get more viscous but less flammable. |
Boiling point, viscosity and flammable |
|
|
How does baking powder make a cake rise? |
The carbon dioxide released during thermal decomposition expands in the heat, helping cake rise. |
|
|
|
What is the thermal decomposition of baking powder? (Word and symbol) |
Sodium hydrogencarbonate -> sodium carbonate + carbon dioxide + water
2NaHCO3 -> Na2CO3 + CO2 +H2O |
|
|
|
How Can you test for carbon dioxide? |
Bubble it through limewater and if it is present it turns milky. |
|
|
|
What happens when you cook a potato? |
The cellulose cell wall breaks down by heat, making it softer. The starch grain inside the cell swell up as they absorb water. These starch grains then move around the cell making it easier to digest. |
|
|
|
Why is a potato hard to digest when raw? |
Because cellulose is difficult for humans to digest. |
|
|
|
What happens when an egg is cooked? |
The protein molecules change shape when heated. The heat energy from cooking breaks the chemical bonds in the protein so, the molecule forms a new shape as it is denatured. |
|
|
|
How can you tell that a chemical change has happened? (3 things) |
A new substance is made An energy change happens The change is irreversible |
|
|
|
What are the four types of additives and their uses? |
Food colour = makes the food look more appealing. Flavour enhancers = brings out the smell and taste of a food without adding it artificially. Emulsifier = stops oil and water from separating. Antioxidants = helps preserve the food. |
|
|
|
How does food become smelly? |
The fats in the food becomes oxidised by reacting with the oxygen in the air. |
|
|
|
What does an Emulsifier add to the food? |
Texture as it makes it thicker. |
|
|
|
How does an Emulsifier work? |
The hydrophobic tail bonds with the oil molecules and the hydrophilic head bonds with the water molecules. This keeps the oil and water molecules from mixing together so, the mixture doesn't separate. |
|
|
|
How are esters made? |
By esterification. |
|
|
|
What happens during esterification? |
An acid is reacted with alcohol by being warmed up to around 60 degrees. |
|
|
|
What is the General word equation for esterification? |
Acid + alcohol -> ester + water |
|
|
|
What catalyst is used during esterification? |
Concentrated sulfuric acid. |
|
|
|
What are the 5 properties of perfumes? |
1 - easily evaporates 2 - non-toxic 3 - doesn't react with water (sweat) 4 - doesn't irritate skin 5 - insoluble in water |
|
|
|
What are the advantages and disadvantages of animal testing for cosmetics? |
Advantages: To make sure that it is safe to use on humans Good for testing medicines because it could help develop new medicines for animals and humans Disadvantages: Harms the animals Morally wrong for animals to suffer in order to benefit humans Expensive to look after the animals |
|
|
|
How can perfumes be made? |
Naturally and synthetically. |
|
|
|
What does volatility mean? |
How easily a liquid evaporates. |
|
|
|
Why do very volatile liquids evaporate easily? |
Because the attractions between the particles are really weak and easily overcome. |
|
|
|
What is a solution? |
A mixture of a solvent and solute. |
|
|
|
What is the solute? |
The substance being dissolved. |
|
|
|
What is the solvent? |
The liquid the solute dissolves into. |
|
|
|
What does soluble and insoluble mean? |
Soluble = will dissolve Insoluble = won't dissolve |
|
|
|
What is solubility a measure of? |
How much will dissolve of the substance. |
|
|
|
Why is nail varnish insoluble in water? |
Because the attraction between the water molecules and nail varnish molecules is weaker than the attraction between their own particles. So a solution isn't formed as the 2 substances are more attracted to themselves. |
|
