Core Practical: Investigating Rate of Reaction Flashcards
All 7 cards in this deck
What are the steps to measure the rate of reaction between hydrochloric acid and marble chips by collecting the gas?
e.g. marble chips added to 50 cm³ of dilute hydrochloric acid- Measure the acid into a conical flask, add the marble chips and start the timer.
- Immediately fit a bung with a delivery tube connected to a gas syringe.
- Record the volume of gas every 30 s until it stops rising.
Other than collecting the gas, which measurement shows how much carbon dioxide has been produced in a reaction?
The loss in mass of the flask and contents, found by weighing the flask on a balance. The mass falls as the gas escapes.
In the core practical with sodium thiosulfate and hydrochloric acid, what is timed?
The time taken for a cross drawn under the flask to disappear as the mixture turns cloudy. The shorter the time, the faster the rate.
Why is a gas syringe or a 100 cm³ measuring cylinder better than a 250 cm³ measuring cylinder for measuring the volume of gas produced?
It has smaller gradations / higher resolution, so the volume is measured more precisely.
A student investigates the effect of temperature on the rate of reaction between magnesium ribbon and dilute acid. State three variables that must be kept the same.
Concentration of acid, volume of acid, and the mass and size/surface area of the magnesium.
True or false? Eye protection should be worn throughout a rate experiment using dilute hydrochloric acid.
True. The acid is an irritant and can splash or fizz out of the flask.
Sodium thiosulfate and hydrochloric acid are both colourless solutions. What makes the mixture turn cloudy when they react?
A yellow precipitate of sulfur forms.