Basic Stoichiometry Post Lab Homework

Did you ever have a feeling of being in the shoes of Einstein when you are standing in your chemistry lab, mixing all the colorful chemicals in the beaker? It feels good, isn’t it? Well, I had this extremely exhilarating feeling while seeing the reactions taking place in the lab. But when we have to study or explain about the quantitative relationship between the products and reactants in our homework, all that excitement takes a back seat. In fact, searching for basic stoichiometry post lab homework exercises answer key is extremely difficult if you have a vague idea about this topic or are confused.

Sorry, we won’t disclose answer key of Stoichiometry here, but if you need, please submit your details by visiting here :

And because of this, you have to face late submission issues whose outcome you can see in your grade card. So, how to resolve this issue? It’s simple! As both this aspects are important, let me guide you to its effective solution here.

Explaining Stoichiometry

The foundation of Stoichiometry is on law of conservation of mass. It can be expressed as a quantitative relationship between product and reactant, from which you can determine coefficients of balanced equation. These equations help in describing the complete reaction.

Problems related to this subject

Your search for basic stoichiometry post lab homework exercises answer key takes place when you faceproblems in your topic. You will find that in most cases the Stoichiometry problems revolve around 4 aspects. We can also state them as 4 types.

  1. Volume-Volume

In this situation, you may face difficulty in finding the volume of product or reactants when the volume of product or reactants is unavailable.

  1. Mass-Volume

In this case, the problem usually arises when you may face issue in finding volume of gaseous product or reactants when the volume of gaseous product or reactants is unavailable.

  1. Mass-Mass

In this situation, you may face difficulty in finding the mass of product or reactants when the quantity of mass of product or reactants is unavailable.

  1. Mole-Mole

In this case, students fail to find the moles of product or reactants when the quantity of moles of product or reactants is unavailable.

Why getting basic stoichiometry post lab homework exercises answer key is important?

Experiments involving mixing of acids and bases to get a product are the objective in chemistry. However, in Stoichiometry, you have to use the acid – base reaction for determining the results which is done by measurement of temperature changes taking place in that reaction.

Post lab homework in basic stoichiometry is basically about finding out the answers related to the reactions and getting the concept of these reactions cleared. This is because chemical reactions are taken as the core form under this topic. Aside to it, lab works helps in determining the product amount and the calculations related to starting material on per mole basis.

Beneficial aspects of Stoichiometry with use of Algorithmic Approach

In most cases, you will find explanations related to basic stoichiometry post lab homework exercises answer key in inquiry based methods. But, there are other methods too with which you can get the answers. One of those methods is algorithmic approach. Although the process is not straightforward, it is a beneficial aspect of getting the solution.

Some of the effects are as follows:

  • With these approaches, you can identify the proper measurements of reactants to get the asked product
  • It helps you in utilizingthe component data of reactants, thereby limiting the issues that can arise during the experiment
  • It also gives you a proper idea related to quantity comprehension that you need to go through before you start working on your homework exercises.

Important rules related to Stoichiometry

As Stoichiometry is about reactants, products, and their appropriate measurement, there are few rules involved in determining the accurate amount of generated product. The 5 most important rules in this case (while you solve your post lab homework) are:

  • Balancing the equation in an appropriate manner
  • You need to have a clear idea regarding substance quantity that is given in your work. It is better to jot down the quantity 1 line below the substance if it is mole quantity. In case it is a laboratory quantity, it is appropriateto write the substance quantity 2 lines below.
  • Make your decision related to quantity clear on whose basis you want to calculate the reactants. It is better to represent it with‘?’ and follow the same procedure of substance quantity representation as explained in the above step.
  • Taking the help of diagrams to explain your answers in your homework will give it a better scalability level. You can explain your answers using arrows. This procedure highlights the reactions. In this process you can elucidate quantity to moles, moles related to unknown quantity, and unknown laboratory quantity.
  • The final step involves calculation of every reactant quantity.

I hope that this information did come to your help regarding basic stoichiometry post lab homework exercises answer key. As this info is a small approach to give you an idea about this topic and its important facets and answers related to both theoretical and practical sections. If you want to have elucidated explanations and info related to basic stoichiometry post lab work, there are selected professional websites offering you adequate data.


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teacher involved


Phet (Reactants/products/leftovers)

Topics related to the resource

Chemical reactions, law of Conservation of Particles, limiting reactants in molecular approach (particle level)

Examples of learning objectives

The simulation is designed to give students
• a conceptual understanding of limiting reactants, rather than practice at solving algorithmic problems that require mass/mole conversions.
• reinforcement of concepts related to chemical equations
It relates the real-world example of making sandwiches to chemical reactions by representing particles as space-filling models. The simulation does not include ionic compounds.
The students are intended to
• Describe what limiting reactant means using examples of sandwiches and chemicals at a particle level.
• Identify the limiting reactant in a chemical reaction given the initial amounts of two reactants and the chemical equation
• Use their own words to explain the Law of Conservation of Particles (atoms/molecules) by using examples of sandwiches and chemical reaction.
• Predict the amounts of products and leftovers (excess reactants, reactants that do not react) after reaction using the concept of limiting reactant.
• Predict the initial amounts of reactants given the amount of products and leftovers using the concept of limiting reactant.
• Translate from symbolic (chemical formula) to molecular (pictorial) representations of matter.
• Explain how subscripts and coefficients are used to solve limiting reactant problems.

Practical information regarding the use
of the site/simulation...

The simulation is very user friendly. The only guidance needed is in the sequence of the three possible choices: sandwich shop/real reaction/game

Information about the class

About 20 students (aged 16-17), 2nd grade of upper secondary school (in the science track) in the very first lessons. Students have already been taught (in the 1st grade of upper secondary school) the principles of chemical reactions and stoichiometry but did not have satisfactory practice and have not yet known chemical equilibrium.

Suggestion for use

• A lab equipped with 10 computers is used. A link to the simulation is saved to the desktops of the lab computers, so that students had no need to access the internet.
Students are told to work in pairs and to use the activity sheet for guidance and for homework. During the activity, the teacher goes about the room to answer student questions.
The model A.«prediction» - B.«experiment by means of simulation» - C «comparison of results to predictions- explanation», and D «conclusions-discussion- conceptual understanding in molecular level» is followed in 2 parts:
1. Making sandwiches: it is used as a simulation of a two-reactant synthesis reaction with a simple mole ratio 2:1:1. First they complete the predictions, then they familiarize themselves with the simulation and check their answers. Finally they explain their errors. One reactant will be limiting, while the other in excess.
2. Real Chemical Reactions (synthesis of water and ammonia and combustion of a hydrocarbon like methane)
• Finally the best part:
3. Game. A challenge is given to every pair to obtain the best score in the lab group. They can take it for homework and note their initial score and their best score.

• Due next time, students have to fill in part D, to play the game for practice and to fill the post-lab homework sheet. It contains problems that require mass/mole conversions and distinction between atoms of every species (constant) and molecules of reactants and products (different).
The test questions are taking into consideration the chemical education research literature and are designed to elicit student misconceptions and difficulties to transfer from microcosmos (simulation) to macrocosmos (moles/ masses). Also this is not included in the simulation. The contribution of discussion with an open-response version of the post-test is recommended.
It is remarkable that the simulation in molecular approach does not allow the production or reaction of fractions and allows null product.

Insights into student
use / thinking

• Students enjoy the simulation as a game and understand very well their wrong predictions. Molecular models are very helpful in understanding chemical equations(chemical symbols)
• Students usually think that the reactant with the least relative amount is the limiting one. It is helpful to watch the histograms of consumption/production
• Students usually confuse the coefficients in chemical equations with the subscripts in chemical formula. This simulation makes clear that the rule in real reaction is the ratio (coefficients) and the conservation of atoms in contrast with the production of new different (in quality and quantity) molecules.
• The wrong predictions are mainly made when there is no product. The simulation helps students to understand it but from the teacher viewpoint, I believe that there is no reason to explain to students something that could never happen! That is, to be in the condition of an amount of atoms that cannot form at least 1 molecule!. In addition, a misconception can be caused when there are both reactants in leftovers (this happens in reversible equations). We use to say that the limiting reactant is finished in one-way reactions…

Teacher’s conclusions

The experience of the application was very positive :
1. Very good understanding of the conservation of atoms and production of different molecules according to the mole ratio of the chemical equation.
2. Very good understanding of the concept of the limiting reagent. The difficulties of students with analogies are alleviated due to the simulation
There are some points that need attention and that could be optimized as far as the understanding of massive production and chemical equilibrium is concerned. Two consideration are the following:
1. Do not allow to have no product (≠0) in order to use fractions in moles ratio.
2. Give the choice of reversible equations in chemical equilibrium in order to help students understand the concept of reaction yield in combination with limiting agent. For example it would be very intelligible for students in the sandwich shop to understand that if we make 100 sandwiches and we sell 60 then the leftovers are the reactants for 40 sandwiches (of course there is need to reiterate that it is dynamic equilibrium, not static)

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