Chemistry Unit 2 Flashcards
(44 cards)
State what is always formed in a chemical reaction.
A new substance.
State four signs that a chemical reacis occurring.
•Heat being given out- Exothermic reaction.
•Heat taken in- Endothermic reaction.
•Bubbling and fizzing- Effervescence.
•Colour change.
•Solid forming- Precipitate.
Explain the difference between an exothermic and endothermic reaction.
Exothermic reactions release heat into the atmosphere while endothermic reactions absorb heat.
How does changing the temperature of a reaction affect the rate of reaction?
If the heat is increased, the reaction will happen faster
How does changing the concentration of a reactant effect thd rate of reaction?
If the concentration is decreased, then the reaction will slow, but if it is increased, it will speed up.
How does particle size affect a reaction?
It speeds up the rate of reaction
What is the effect of a catalyst on a chemical reaction?
It speeds up the rate of reaction
What is the effect of a catalyst on a chemical reaction?
It speeds up the rate of reaction
Where can an enzyme and a catalytic converter be found?
They can both be found in the human body- breaking down proteins into aminic acids.
Why are enzymes and catalytic converters important?
They ate important because without catalytic converters, which in this case are enzymes, proteins would not be broken down and they would be impossible for the body to absorb.
How do you make an experiment a ‘fair test’?
You can make an experiment a fair test if all variables are the same except for one.
How do you calculate the rate of reaction?
Average rate=change in quantity÷change in time
What is a compound?
A compound is two atoms chemicaly bonded together
What is a molecule?
A molecule is a group of two or more atoms held together by covalent bonds.
Does covalent bonding exist between non-metal elements?
Yes
What is a covalent bond?
It is the electrostatic attraction between both nucli and pair/s of electrons in the atoms that are part of the bond.
How do non-metal atoms get a full outer shell of electrons?
Through joining covalently.
What is ment by a lone pair of electrons?
A pair of electrons are electrons that are in the outer shell of a covalently bonded atom but are not involved in the actual bonding.
What does a molecule with a linear shape look like?
Generally, it has a line-like shape.
What does a molecule with an angular shape look like?
It looks like an angle
What does a molecule with a trigonal pyramidal shape look like?
The shape resembles, as the name suggests, a triangular pyramid.
What does a molecule with a tetrahedral shape look like?
It looks like a tetrahedron.
What’s the difference between covalent molecules and covalent networks?
Normally, covalent molecules are relatively small groups of atoms. However, if the covalent bonding continues throughout the substance, then huge networks can be built up- these are covalent networks
What are three covalent network elements?
Carbon, silicon, and boron
