True or false?

Question

Please tell me if these are true or false. Only tell me if you are definatly sure. Ta!!!
1.Catalysts are specific to certain reactions.
2.Reations slow if catalysts are used.
3.Enzymes increase the activation energy.
4.Reactions slow down if diluted.
5.Inreasing concentration increases the rate of reaction.
6.Pressure increases the rates of gaseous reactions.

Thanks for every one who answered. The correct answers are :
1. True
2. False
3. False
4.True
5. True
6.True
Thanks.

Answer 1

1.true
2. false- catalysts are used to speed up reactions
3. false- they simply break down or join molecules, they are completely separate from the energy levels. not to be confused with catalysts, which lower the activation energy, thus making reactions faster
4.true- it spaces the particles further apart, making them less likely to collide and cause a reaction
5.true- this increases the likelihood of successful collisions
6.true- see above, it forces the particles closer together.

Answer 2

1.Catalysts are specific to certain reactions. TRUE

2.Reations slow if catalysts are used. FALSE.
You can use them to both increase or decrease the rates of reactions.

3.Enzymes increase the activation energy. FALSE.
They provide an alternative path for the reaction which usually has a lower activation energy. That's why enzymes are catalysts.

4.Reactions slow down if diluted. TRUE
Concentration affects the rates of reactions.

5.Inreasing concentration increases the rate of reaction. TRUE
Concentration affects the rates of reactions. However you should remember that there are other factors too.

6.Pressure increases the rates of gaseous reactions. FALSE
It depends on the reaction based on L'Chatelier's principle.

Haber Process: N2 (g) + 3H2 (g) = 2NH3 (g)
As there are 4 moles (1+3) of substances on the left and 2 moles on the right, an increase in pressure will result in a shift to the right, in this case. You have to look at the total number of moles (of gaseous components only) on both sides.

Answer 3

1. Short answer yes and no. Some catalysts are reaction specific others are more general.
2. Catalysts can slow reactions down,they are called inhibitors.
3. Wrong. Enzymes lower the activation energy by providing a different mechanism for the reaction.
4. I think you mean the rate of reaction slows if it is diluted. The speed of a chemical reaction is incredibly fast.
5. Yes, up to a point, if the increase of concentration of one reactant actually dilutes the concentration of the other it can reduce the rate of reaction.
6. Increasing pressure will increase the rate of a gaseous reaction if the product contains fewer molecules than the reactants. It will reduce the rate of reaction if there are more molecules in the products than in the reactants. If the number of molecules are the same in the reactants and products then the rate of reaction will increase slightly, (more collisions). All the above assumes that the temperature REMAINS constant.

Answer 4

alright
1. True because they have something called active sites which are specific to a certain compound only
2. False because catalysts are here only to speed up the rate of reactions.
3. False because enzymes actually lower the activation energy of a reaction so as to provide an easier route with less energy requirement for the reaction to proceed.
4. True. this is due to a decrease in the concentration of the molecules of the reactants. when you have less molecules, there are less and less fruitful collisions to form the products. therefore reactions slow down

5. True. it uses the same logic as the bove question. when you increase the concentration, you are in fact increasing the number of molecules found in the reactants. hence, there will be more and more fruitful collisions and there will more formation of products. therefore, the rate of reaction increases.

6. True. when you increase pressure, you are forcing the molecules of the reactants to come closer together and this will induce more fruitful collisions resulting in an increase in the formation of products. there will be more fruitful collisions because there will be less space for the molecules to move about freely. imagine you and your friends in a closed room without any opened window. you are 10 in all. you can move about quite easily in the room as it is large enough. now let's imagine that there is a certain mechanism which force the walls to close on you by applying pressure on them. the space in which you were moving will be reduced considerably and you will have more difficulty in moving about without colliding with someone, the same process happens in the gas reactants.

Hope it helps

Answer 5

1. True
2. False - catalysts are used to speed up reactions
3. False - enzymes are biological catalysts and work by lowering the activation energy
4. True - the 2 reacting species have less chance of meeting one another if diluted
5. True - opposite of above
6. True - increasing the pressure will bring the gaseous molecules closer together and hence have more chance of colliding therefore speeding up the reaction

Answer 6

1.Catalysts are specific to certain reactions. >>>> T
2.Reations slow if catalysts are used. >>>>>> F
3.Enzymes increase the activation energy. (No idea)
4.Reactions slow down if diluted. >>>>>> F
5.Inreasing concentration increases the rate of reaction. >>>> T
6.Pressure increases the rates of gaseous reactions. >>>>> T

Answer 7

There is some confusion here when you say catalyst.

Catalyst refers to organic or inorganic reactions. Enzymes are a specific type of catalyst used in biological systems and biochemical reactions.

1. So for an organic or inorganic catalyst. (not an enzyme which are specific for individual reactions) the anser is ..

*False* (e.g. platinum is a widely used catalyst for many reactions)
http://education.jlab.org/itselemental/ele078.html


2. False
Catalyst (by its very definition) increase the rate of reactions.

3. False,
Enzymes decrease the energy "hill" (activation energy) of the
reaction speeding up the reaction,

4. ITrue
For inorganic, organic and biochemical reactions,.

5. True

6. True

Hope this answers your questions.

Answer 8

1- yes every reaction has its own catalysts
2- No Catalysts by definition makes the reaction faster and more efficient.
3- i do not know.
4-No water is a must to complete every reaction well
5- no water is a must so concentration is lower for better reactions.
6- Yes

Answer 9

1) True
2) False (overall)
3) False (Majorly decrease it)
4) True
5) Not always, depends on what type of reaction it is, and which reactant is being increase
6) Same as 5 - depends on which side of the reaction is favoured by an increase of pressure. Reaction will do equal and opposite to lower pressure - i.e. move to side with less moles.

Answer 10

all true except for number two and number three - a catalyst is used to speed up a reaction, not to slow it down, and enzymes are useful because they lower the amount of energy needed for a reaction