Conservation of mass apply
Use the chemical equation to answer the question.
2Na + Cl2 → ?NaCl
In the reaction, sodium and chlorine combine to produce sodium chloride. In an instance when eight sodium chloride molecules are produced, how many diatomic chlorine molecules went into the reaction?
can i just get the answer at this point yall just confusing me more
1. Why are open systems inappropriate for studying the conservation of mass?
-Matter may be lost to or gained from the surroundings.
2. A student claims that the reaction of hydrogen and oxygen to form hydrogen peroxide is evidence supporting the claim that mass is conserved in a reaction. The chemical equation the student uses for the reaction is shown.
H2 + O2 → H2O2
Does this evidence support the claim? Why or why not?
-Yes, it supports the claim because the equation is balanced.
3. A student records the masses of two reactants (baking soda and vinegar), and then mixes them. The reactants bubble and foam, forming a paste. The student measures the mass again, and the final mass is slightly less than the sum of the initial masses. Considering that mass is supposed to be conserved, which statement is a possible explanation for this "loss" of mass?
-The bubbling indicates a gas was formed, so some atoms formed gas; therefore, mass was transferred to the atmosphere.
4. Which quantity is used to define 1 atomic mass unit?
-one-twelfth the mass of a neutral carbon atom
5. Use the equation to answer the question.
FeCl3 + 3NH4OH → Fe(OH)3 + 3NH4Cl
Which statement about the equation is correct?
-Mass is conserved because the number of each atom in the reactants equals the number of each atom in the products.
6. The atomic mass of nickel (Ni) is 58.693 amu, and the atomic mass of chlorine (Cl) is 35.45 amu. Which molar mass is correct for nickel chloride (NiCl2)
-129.59 g/mol
7. When the products of a reaction are known, which fact can be deduced about the reactants?
-the number of atoms in the reactants
8. Iron combines with oxygen to produce rust according to the following reaction.
4Fe + 3O2 → rust
Based on the law of conservation of mass, which could be the product of the reaction?
-2Fe2O3
9. Calcium carbonate (CaCO3) can undergo a chemical reaction to produce calcium oxide (CaO) and carbon dioxide (CO2). Which possible masses of calcium oxide and carbon dioxide can form when 200 g of calcium carbonate undergoes this chemical reaction?
-112 g CaO and 88 g CO2
10. Use the chemical equation to answer the question.
2HCl(aq) + Zn(s) → ZnCl2(aq) + H2(g)
The molar mass of hydrogen (H) is 1 g/mol, the molar mass of chlorine (Cl) is 35 g/mol, and the molar mass of zinc (Zn) is 65 g/mol. When 130 grams of zinc react completely in hydrochloric acid (HCl), how much is the total mass of the products?
-274 g
11. Propane reacts with oxygen to produce carbon dioxide and water according to the following equation.
C3H8 + 5O2 → 3CO2 + 4H2O
Which ratio of components is correct?
-`For every 3 moles of carbon dioxide produced, 5 moles of oxygen react.
12. Elements A and B react according to the following equation.
4A + B2 →2A2B
The molar mass of A is 12 g/mol. The molar mass of B is 4 g/mol. The molar mass of A2B is 28 g/mol. When the goal of the reaction is to produce 112 g of the product, how many grams of reactant A should be present initially?
-96
13. The molar mass of BF3 is 67.81 g/mol. How many molecules of BF3 are there in 2 g?
-1.776×1022
14. Can the law of conservation of mass be applied when cooking? In one to two sentences, explain why or why not.
- yes the law of conservation holds that mass can not be destroyed but can only take on different forms. So if 5 g of water becomes a gas it becomes 5 g of water vapor. The mass of the liquid water is simply transferred into the mass of the newly formed water vapor.
15. The molar mass of ammonium acetate is 77.083 g/mol. A student uses 0.100 mol of ammonium acetate in a chemical reaction. The student claims that the reaction uses (0.100 mol)(77.083 g/mol)=7.71 g(0.100 mol)(77.083 g/mol)=7.71 g of ammonium acetate, which has (7.71)(6.022×1023)=4.64×1024(7.71)(6.022×1023)=4.64×1024 molecules.
In one to two sentences, explain the mistake that the student made and determine the correct number of molecules of ammonium acetate used in the reaction.
-the mistake here is the fact the student turned the moles back into mass and then multiplied the mass by Avogadro's number (6.02 x ), which gave him a false answer. To get the correct answer, he had to multiply the number of moles of ammonium acetate by Avogadro's number for the number of molecules.
Number of molecules = Moles times avogadro's number
Number of molecules = 0.100 times (6.02times10^23)
Number of molecules = 6.02 times 10^22
The correct number of molecules of ammonium acetate used in the reaction is 6.02 x mo
the answer is four.
You didn't get any of what she said because she didn't answer the question. However. what This8thGradeGirl0_0 said about combination and decomposition reactions is true.
The reaction is question is 2Na + Cl2 ==> 2NaCl. The question is how many Cl2 molecules are needed to produce 8 molecules of NaCl. You can see from the equation that it takes half as much Cl2 to produce 1 molecule of NaCl; therefore, it must take 4 of Cl2 to produce 8 NaCl. I should point out, also, that the reaction is read as 2 MOLES of Na react with 1 MOLE Cl2 gas to produce 2 MOLES NaCl. While it is true that the stoichiometry holds for MOLECULES as well, the reaction is about MOLES and not MOLECULES.
the answer is four
Hope this helps :)!
The reaction 2Na + Cl2 = 2NaCl is an example of Combination reaction. Decomposition reaction will occur when one reactant breaks down into two or more products, AB => A + B. In Combination Reaction, two or more elements/compounds combine to form a single compound, A + B => AB.
I didn't get any of what you saying lol
one
two
four
eight
Okay.
The balanced equation is 2Na(s)+Cl2(g) → 2NaCl(s)
okay so the answer is 2?
Yes.
Wait, so "Drbob222" you're basically saying that I'm wrong but I'm also right at the same time?
No. You must not have read what I wrote. Go back and read it again and note especially the part of the sentence that starts with "therefore, it must take ........"
@This8thGradeGirl0_0. Yes, I'm saying your answer is wrong; i.e., you answered the question incorrectly. However, I also said that what you wrote about combination and decomposition reactions is correct. But the original question was NOT about combination and decomposition reactions. The original question was about the stoichiometry of Cl2 and NaCl in the reaction given.
So after what you're saying the answer is 4 then right?
You said the question is how many Cl2 molecules are needed to produce 8 molecules of NaCl. You also said that it must take 4 of Cl2 to produce 8 NaCl.
So the answer has to be 4.
@DrBob222, I'm curious. You say the reaction involves moles, not molecules. But do not the molecules do the reacting, one at a time? If all you had were a few molecules, would the reaction not occur? Or is this a matter of vast numbers of molecules joining and splitting, in some kind of quantum foam? In other words, after the reaction is complete, do the atoms still swarm about in a froth of interactions, so that any sample will appear to have the required numbers of atoms? Or is everything just a jumble of ions that act like molecules when examined?
The more I learn about quantum mechanics, the less certain I am about anything in the real world! :-(
2Na + Cl2 ==> 2NaCl
Yes, since it takes 1 molecule of Cl2 to produce 8 molecules of NaCl, according to the equation, then it must take 4 molecules Cl2 to produce 8 molecules of NaCl. You can see that without a math equation but if you want to do it up right, use the math equation, the equation that will convert ANY part of the equation to ANY OTHER part of the equation, it looks like this.
8 molecules NaCl x (1 molecule Cl2/2 molecles NaCl) = 8 x 1/2 = 4. Notice that the denominator of the fraction (that's molecles NaCl) cancel with the "molecules NaCl) to leave units of "molecules Cl2) which is the unit you want for the answer.
@Shottaflow3k. I don't see how you can be confused. ALL of my responses have used 4 as the answer.
So all we had to do was figure out according to the equation how much CI2 it took to produce 8 molecules?
@This8thGradeGirl0_0.
That's right. It's just a stoichiometry exercise.
so Dr. Bob after saying all of that that means that the answer must be 8?
@ oobleck. "DrBob222, I'm curious. You say the reaction involves moles, not molecules. But do not the molecules do the reacting, one at a time? If all you had were a few molecules, would the reaction not occur? Or is this a matter of vast numbers of molecules joining and splitting, in some kind of quantum foam? In other words, after the reaction is complete, do the atoms still swarm about in a froth of interactions, so that any sample will appear to have the required numbers of atoms? Or is everything just a jumble of ions that act like molecules when examined?"
No, what I said was that the reaction is READ AS moles and not molecules and that's because the equation, by definition, is about moles and not molecules. Of course molecules do the reacting and enough molecules make a mole. I just didn't want the student to continue using molecules when it isn't the appropriate language.
The question is the start of the problem. If I wanted to really do it up brown I would have converted 8 molecules of NaCl to moles NaCl, converted that to moles Cl2 and converted back to molecules. Can you imaging the confusion that would cause with the student? So I used molecules and simply pointed out that the equation meant moles. Lo and behold the student was confused anyway. Perhaps I'm being too nit picky but then I'm good at that. Actually the reaction is so much more than the equation. We must break the Cl-Cl bond, then we must vaporize/ionize the Na solid atom, transfer the electron etc etc. I don't picture a quantum froth at the end but I see a sea of equal numbers of Na^+ and Cl^- in a solution/crystal/whatever. Speaking of quantum froth, we are taught in all of our undergrad courses how the atom is constructed. We count electrons. protons, neutrons, quarks, mesons and we talk about the nucleus and the electrons in their "outside" shells. In other words we operate in a world where we want to SEE an atom and SEE the reactions. That continues through graduate school and into life. But the TRUE picture, according to the quantum guys are these lines and pages of math equations where an equation describes all that goes on in atoms/molecules/reactions. I've had my fair share of quantum physics courses but I prefer to stick to the pictures. It helps me understand what is going on much better than a Schroedinger equation any day of the week. The short answer to your question is "of course reactions start between individual atoms and molecules but equations, by definition, are all about moles."