Answer:
C. To determine how efficient reactions are.
D. To determine how much reactant they need.
Explanation:
When you are doing a reaction, you are hoping for a percent yield to close of 100%. You make the reaction and determine how many product you obtain. If you know the percent yield of a reaction you can calculate the amount of reactant you need to obtain a determined amount of product.
Having this in mind:
A. To balance the reaction equation. false. To calculate percent yield you need to balance the reaction before. You don't use percent yield to balance the reaction
B. To determine how much product they will need. false. You determine how much product you obtain after the reaction. How much product you need is independent of percent yield
C. To determine how efficient reactions are. true. A way to determine efficience of a reaction is with percent yield. An efficient reaction has a high percent yield.
D. To determine how much reactant they need. true. If you know percent yield of a reaction you can know how many reactant you must add to obtain the amount of product you want.
Answer:
D
Explanation: iIt is a neutralization reaction and neutralization reaction is a reaction between and acid and base to give salt and water. In the question above, Ca(OH)2 is the base and HCl is the acid, Ca(Cl)2 is the salt and H2O.
Answer: Option (c) is the correct answer.
Explanation:
Activation energy or free energy of a transition state is defined as the minimum amount of energy required to by reactant molecules to undergo a chemical reaction.
So, when activation energy is decreased then molecules with lesser amount of energy can also participate in the reaction. This leads to an increase in rate of reaction.
Also, increase in temperature will help in increasing the rate of reaction.
Whereas at a given temperature, every molecule will have different energy because every molecule travels at different speed.
Hence, we can conclude that out of the given options false statement is that at a given temperature and time all molecules in a solution or a sample will have the same energy.
Answer:
The correct answer to the question is
a. it contradicted accepted principles of physics
Explanation:
The idea of electrons moving in orbits contradict classical electromagnetism idea whereby electrons are expected spiral to the nucleus instantaneously. Meaning all atoms are supposed to be unstable a postulation that contradicts observable evidence.
Bohr's model of the atom consists of atoms, having electrons in specific orbits. The theory explains spectroscopy and enabled the determination of the constituent atoms present in distant stars.
