Untitled Deck Flashcards
Define Catalyst.
A catalyst is a substance which changes the rate of reaction but is unchanged at the end of the reaction.
Define Concentration.
The abundance of a substance within a given area, or the abundance of a constituent divided by the total volume of the solution or mixture.
Define Surface Area.
Surface area is the exposed area of a solid substance.
Define Temperature.
The average kinetic energy of all the atoms or molecules of a solution, mixture, or substance.
Define reaction rate.
The reaction rate is a measure of how quickly a chemical reaction occurs.
Give an example that explains why surface area is a factor in reaction rate.
In a reaction between magnesium metal and hydrochloric acid, magnesium atoms must collide with the hydrogen ions. When the magnesium atoms form smaller lumps, the number of collisions per second between magnesium and hydrogen is higher, and the rate of reaction is faster.
How can you identify a chemical change?
In a chemical change, something new is formed. Look for: A change in temperature, bubbles (gas formation), a permanent colour change, formation of a new solid (precipitate), or energy produced/absorbed.
How much Catalyst is needed to increase the rate of reaction for how much Reactant?
Only a very small amount of catalyst is needed to increase the rate of reaction between large amounts of reactants.
How to Balance a Chemical Equation?
- Write out the number of atoms on each side of the equation for each element. 2. Adjust an unequal element that is part of a compound. 3. Repeat until all elements within only compounds are fixed. 4. Adjust the pure elements.
How to write a chemical formula?
For a molecule/compound, use the chemical symbols of the elements it contains. E.g., NaCl. If the molecule contains more than one atom of an element, use numbers to show this: e.g., Na2SO4.
When does the neutralisation reaction occur?
Right when the amount of product stops increasing. This is because if the reactants are too small, only a partial neutralisation reaction will occur, and if too much, there will be excess reactant.
What happens when the temperature increases?
If the temperature is increased: reactant particles have more energy, move more quickly, collide successfully more often, and the rate of reaction increases.
What are 2 examples of slow chemical reactions?
The chemical reactions that cause concrete to set and rusting.
What are Fossil Fuels made of?
Fossil fuels are made of hydrocarbons - carbon compounds made of carbon and hydrogen atoms.
What are some examples of combustion reactions?
A candle burning, petrol in a car engine.
What are some rules of the chemical equation?
The reaction direction points from the Reactants to the Products; the reactants are on the left, products on the right.
What are the factors that affect reaction rate?
Surface area, concentration of a reactant, pressure, temperature, and presence/absence of a catalyst.
What are the four components of a chemical reaction?
Reactants, products, reaction direction, and physical state of each component. States: (s) = Solid, (l) = Liquid, (g) = Gas, (aq) = Aqueous.
