The cards Question What is the rate of reaction? Tap to flip Answer The speed with which a chemical reaction takes place. Question How is rate of reaction measured? Tap to flip Answer By the amount of a reactant used, or the amount of product formed, in a given time. Question How does the rate of most chemical reactions change as they progress? Tap to flip Answer They start more quickly and then slow down. Question What is the mean rate of reaction? Tap to flip Answer The average rate at which reactants are converted into products over a given period of time. Question What is the instantaneous rate of reaction? Tap to flip Answer The rate at which reactants are converted into products at a specific moment in time. Question How do you find the instantaneous rate at a given time from a rate graph? Tap to flip Answer Draw a tangent to the curve at that time and calculate its gradient; reading values off the graph is not enough. Question What is a tangent? Tap to flip Answer A straight line that touches a curve at exactly one point without crossing it. Question How is the mean rate of reaction calculated from mass of gas produced? Tap to flip Answer Mean rate = total mass of gas produced ÷ total time of reaction. Question What are accurate measurements? Tap to flip Answer Measurements that are close to the true value. Question What are precise measurements? Tap to flip Answer Measurements with very little spread from the mean value; they lie close to each other. Question For which reactions is an upturned measuring cylinder suitable for collecting gas? Tap to flip Answer Reactions producing large volumes of gas at moderate rates. Question Which equipment is ideal for measuring small volumes of gas with high precision? Tap to flip Answer A gas syringe. Question How should the size of gas-measuring equipment be chosen? Tap to flip Answer It should be close to the volume of gas expected to be produced. Question What can a light sensor measure in a reaction that produces a precipitate? Tap to flip Answer The percentage of light transmitted through the reaction mixture. Question What does collision theory state? Tap to flip Answer Particles must collide, and with sufficient energy, in order to react. Question What is activation energy? Tap to flip Answer The minimum energy that particles must have in order to react. Question Does every collision between reactant particles cause a reaction? Tap to flip Answer No. Particles must collide with the activation energy for the collision to be successful. Question Why does increasing the surface area of a solid reactant increase the rate? Tap to flip Answer More reacting particles in the solution can collide with the solid's particles each second. Question Why does increasing the concentration of a reacting solution increase the rate? Tap to flip Answer There are more reactant particles, so they collide more frequently. Question How does increasing temperature generally increase the rate of reaction? Tap to flip Answer It increases the energy and the frequency of collisions between particles. Question Why does increasing the pressure of reacting gases increase the rate? Tap to flip Answer Reactant particles are pushed closer together, so they collide more frequently. Question How does cooling a reactant affect the rate of reaction? Tap to flip Answer It decreases the rate by reducing the energy and frequency of collisions. Question Does raising the temperature change the amount of product formed? Tap to flip Answer No. The reaction goes faster, but the amount of product stays the same; the reactants are the limiting factor. Question Which have the larger surface area: small marble chips or large marble chips of the same mass? Tap to flip Answer The smaller marble chips. Question How does surface area affect the rate of reaction? Tap to flip Answer The larger the surface area, the faster the rate. Question Does using calcium carbonate powder instead of chips of the same mass produce more carbon dioxide? Tap to flip Answer No. The same mass of carbon dioxide is produced; a larger surface area does not give more product. Question What is the independent variable in an investigation? Tap to flip Answer The single variable that is changed. Question What is the dependent variable in an investigation? Tap to flip Answer The single variable that is measured or observed. Question What are control variables? Tap to flip Answer Variables that are kept constant in an investigation. Question When equal amounts of magnesium react with excess acid of different concentrations, how does the volume of gas compare? Tap to flip Answer The same volume of gas is produced for all concentrations. Question What does it mean for a reactant to be in excess? Tap to flip Answer It is present in a greater amount than needed to react completely with the limiting reactant. Question What does the reaction between sodium thiosulfate solution and hydrochloric acid produce that clouds the mixture? Tap to flip Answer A precipitate (of sulfur). Question In the disappearing cross experiment, does the reaction stop when the cross can no longer be seen? Tap to flip Answer No. Enough sulfur precipitate has formed to hide the cross, but the reaction continues until the reactants are used up. Question What is a precipitate? Tap to flip Answer An insoluble solid formed when two solutions react together. Question What is an end point method? Tap to flip Answer A method that measures the progress of a reaction until it reaches completion or a chosen point, such as a colour change. Question What is an advantage of measuring an end point when comparing reactions? Tap to flip Answer It allows direct and simple comparison of reaction rates. Question When does a parallax error occur? Tap to flip Answer When a measurement is not taken at eye level. Question How can the bung in a conical flask affect gas volume measurements? Tap to flip Answer It can displace a small volume of gas, which affects the accuracy of the measurements. Question What is a catalyst? Tap to flip Answer A chemical that increases the rate of a reaction without itself being used up. Question How does a catalyst affect the activation energy of a reaction? Tap to flip Answer It reduces the activation energy needed. Question What are enzymes? Tap to flip Answer Biological catalysts. Question Does a catalyst increase the amount of product formed? Tap to flip Answer No. It increases the rate at which products form, not their quantity. Question What do reaction profiles show? Tap to flip Answer The energy of the reactants and products in a chemical reaction. Where this deck sits in the curriculum Curriculum National Curriculum for England Stage GCSE (Years 10–11) Course GCSE Chemistry Unit Rate of reaction Exam boards AQA, Edexcel, OCR Tiers foundation and higher England's National Curriculum sets what is taught; the units and their order are Oak National Academy's. Flash Feed is not affiliated with Oak or any exam board.
How this deck was checked On 2026-11-02, every card was compared with its source: the lessons of Oak National Academy, a public body funded by England's Department for Education that publishes lessons for the national curriculum. Because the cards come from those lessons, no second source was sought. The comparison was done automatically, not by a teacher, so a card can still be wrong. Flash Feed is not affiliated with any source named here.
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A Chemistry lesson by Oak National Academy licensed under Open Government Licence (OGL)
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