Chemistry Flashcards
(24 cards)
For investing a rate of reaction with a syringe, should you use cotton or a stopper?
Stopper.
For investigating the rate of reaction with a balance, should you use a stopper or cotton wool?
Cotton wool
What takes longer to react, chips or powder and why?
Powder because more particles are exposed with smaller pieces, meaning smaller objects like powder react faster than chips or bigger objects.
Does higher temperature speed up reaction?
Yes because of kinetic energy of the particles, making them move faster and have more successful collisions.
What is a catalyst?
A substance that can increase the rate of reaction and not being lowered itself. It does this by lowering the activation energy.
Does higher concentration speed up reaction?
Yes because there are more frequent collisions as the particles are closer.
Does a larger size speed up reaction?
No.
When do reactions end? (looking at a graph)
When the line flattens.
How do you calculate the mean reaction?
Take between the seconds (first 5 sec would be from 0-5) and divide that by the substance produced/lost (20/5=4cm3/s)
What is the difference between a conical flask and a beaker?
Conical flask is round at the top.
If you see an upside down measuring cylinder, what does it mean?
It means gas, where the white ends, measure from.
If you change from chips to powder, what would happen to a graph?
A steeper gradient, same leveling out point.
What is activation energy?
The minimun energy needed for a reaction to occur.
If you added a catalyst to an experiment about the volume of gas produced, does that make more gas?
Marginally (from 60 to 61) or not.
How should a line of best fit look?
On the dots, with potentially ONE anomaly.
Why might a “time taken” experiment have an anomaly?
Ended too fast or slow, temperature, concentration
What can keep a consistent temp. during an experiment?
Hot water bath.
How to draw a tangent?
- Line on point to the edges of the squared paper
- make a 90° triangle,
- measure height,
- divide by base length.
- Answer unit/time (0.28g/s)
How to answer 6 mark?
2 or 3 valid comparisons explained fully.
How many decimal places should you round to?
2dp (9.12 and not 9.118)
On a graph, what does temperature do?
Steeper gradient, double the temperature reaches the maximum faster barely (steeper gradient)
What does concentration do on a graph?
Double the maximum gas, half halves the maximum gas (if the original was 60, double concentration would be 120, half would be 30).
However, double the concentration has a more flattened graph to reach the maximum.
Also flatlines faster.
What does half the volume do?
Reaches half the original value.
What does powder do?
Slightly steeper gradient than double the temperature.
