All chemical reactions involve either breaking bonds, forming bonds, or breaking and forming bonds.
When conducting a chemical reaction, the compound composition is used (example: Fe+S= FeS)
In the final product, all of the same molecules are used as what we started with.
The same amount of molecules is not necessary for all of the molecules. They do not have to be balanced because if they are, they would make completely different compounds that what were needed. (example H2+O2 H2O. H4+O2=H2O This is now considered to be balanced because it shows us how many product and reactant will be present. Each atom in the reactant side will be present in the product side.)
The Law of Conservation of Mass: There can never be more or less atoms before the reaction as compared to after the reaction. This also means that it will have the same mass before and after the reaction.
Chemical reactions rearrange the atoms present.
Chemistry is the basis of almost all science and benefits thereof, without chemistry we would not have many of the wonderful things we have access to today, like normal milk, its pasteurized by a process that requires basic knowledge of chemistry.
CHEMICAL REACTIONS TUTORIAL QUESTIONS:
1. Starting materials in a chemical reaction are called reactants.
2. The ending materials in a chemical reaction are called products.
3. The arrow indicates a chemical change has taken place.
4. All reactions have one thing in common: there is a breaking, bonding, or both of chemical bonds.
5. Chemical reactions always involve broken old bonds, forming of new bonds, or both.
6. In all reactions we still have all of the atoms at the end that we had at the start.
7. In every reaction there can never be any more atoms or less atoms on one side than there are on the other.
8. Chemical reactions only balance in the atoms that are already there.
9. Let’s represent a reaction on paper. For example, hydrogen gas (H2) reacts with oxygen gas (O2) to form water
(H2O):
H2 + O2H2O
If we use only the atoms shown, we’d have 4 atoms of H and 3 atoms of O as reactants. This would make 2 molecule of H2O, but we’d have 1 atom of O leftover. However, this reaction only makes H2O.
Remember: reactions are not limited to 1 molecule each of reactants. We can use as many as we need to balance the chemical equation. A balanced chemical reaction shows:
a) What atoms are present before (in the reactants) and after (in the products)
b) How many of each reactant and product is present before and after.
10. So to make H2O from oxygen gas and hydrogen gas, the balanced equation would be:
___4_ H2 + ___2__ O2 ___=__ H2O Which is the same as: 2H2O
11. This idea is called the Law of Conservation of Mass
12. There must be the same coefficients and the same number of atoms before the reaction (in the reactants) and after the reaction (in the products).
13. What is the balanced equation for this reaction?
__2__ Cu + ___1__ O2 =___2_ CuO
14. In the unbalanced equation there are:
Reactants Products
# Cu atoms __2___ = # Cu atoms ___2__
# O atoms ___2__= # O atoms ___2__
15. To balance this equation, we have to add __1____ molecules to the products, because this reaction doesn’t make lone __O___ atoms.
16. When we added a molecule of CuO, now the number of __Cu___ atoms is balanced but the number of _O___ atoms don’t match. Now we have to add more __O___ atoms to the reactants.
17. The balanced equation for this reaction is __2__ Cu + ___1__ O2 =__2__ CuO
This is the same thing as saying:
Reactants # Cu atoms __2___ = # O atoms ____2_ =
Products # Cu atoms ___2___ # O atoms ___2___
18. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) __1___ CH4 + __2___ O2= ___2__ H2O + __1___ CO2
19. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) __1___ N2 + __3___ H2 =___2__ NH3
20. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) ___2__ KClO3 = ____2_ KCl + __3___ O2
21. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) ___4__ Al + __3___ O2 =__2___ Al2O3
SUMMARY
1) Chemical reactions always involve the breaking of bonds, the forming of bonds, or both.
2)The Law of Conservation of Mass says that the same atoms must be the same before the chemical reaction and after the chemical reaction. They must also have the same mass.
3)To balance a chemical equation, you change the coefficient in front of each substance until there are the same number of each type of atom in both reactants and products.
When conducting a chemical reaction, the compound composition is used (example: Fe+S= FeS)When conducting a chemical reaction, the compound composition is used (example: Fe+S= FeS)
In the final product, all of the same molecules are used as what we started with.
The same amount of molecules is not necessary for all of the molecules. They do not have to be balanced because if they are, they would make completely different compounds that what were needed. (example H2+O2 H2O. H4+O2=H2O This is now considered to be balanced because it shows us how many product and reactant will be present. Each atom in the reactant side will be present in the product side.)
The Law of Conservation of Mass: There can never be more or less atoms before the reaction as compared to after the reaction. This also means that it will have the same mass before and after the reaction.
Chemical reactions rearrange the atoms present.
Chemistry is the basis of almost all science and benefits thereof, without chemistry we would not have many of the wonderful things we have access to today, like normal milk, its pasteurized by a process that requires basic knowledge of chemistry.
CHEMICAL REACTIONS TUTORIAL QUESTIONS:
1. Starting materials in a chemical reaction are called reactants.
2. The ending materials in a chemical reaction are called products.
3. The arrow indicates a chemical change has taken place.
4. All reactions have one thing in common: there is a breaking, bonding, or both of chemical bonds.
5. Chemical reactions always involve broken old bonds, forming of new bonds, or both.
6. In all reactions we still have all of the atoms at the end that we had at the start.
7. In every reaction there can never be any more atoms or less atoms on one side than there are on the other.
8. Chemical reactions only balance in the atoms that are already there.
9. Let’s represent a reaction on paper. For example, hydrogen gas (H2) reacts with oxygen gas (O2) to form water
(H2O):
H2 + O2H2O
If we use only the atoms shown, we’d have 4 atoms of H and 3 atoms of O as reactants. This would make 2 molecule of H2O, but we’d have 1 atom of O leftover. However, this reaction only makes H2O.
Remember: reactions are not limited to 1 molecule each of reactants. We can use as many as we need to balance the chemical equation. A balanced chemical reaction shows:
a) What atoms are present before (in the reactants) and after (in the products)
b) How many of each reactant and product is present before and after.
10. So to make H2O from oxygen gas and hydrogen gas, the balanced equation would be:
___4_ H2 + ___2__ O2 ___=__ H2O Which is the same as: 2H2O
11. This idea is called the Law of Conservation of Mass
12. There must be the same coefficients and the same number of atoms before the reaction (in the reactants) and after the reaction (in the products).
| Element | # of atoms in Reactants | # of atoms in Products |
| H | 4 | 4 |
| O | 2 | 2 |
13. What is the balanced equation for this reaction?
__2__ Cu + ___1__ O2 =___2_ CuO
14. In the unbalanced equation there are:
Reactants Products
# Cu atoms __2___ = # Cu atoms ___2__
# O atoms ___2__= # O atoms ___2__
15. To balance this equation, we have to add __1____ molecules to the products, because this reaction doesn’t make lone __O___ atoms.
16. When we added a molecule of CuO, now the number of __Cu___ atoms is balanced but the number of _O___ atoms don’t match. Now we have to add more __O___ atoms to the reactants.
17. The balanced equation for this reaction is __2__ Cu + ___1__ O2 =__2__ CuO
This is the same thing as saying:
Reactants # Cu atoms __2___ = # O atoms ____2_ =
Products # Cu atoms ___2___ # O atoms ___2___
18. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) __1___ CH4 + __2___ O2= ___2__ H2O + __1___ CO2
19. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) __1___ N2 + __3___ H2 =___2__ NH3
20. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) ___2__ KClO3 = ____2_ KCl + __3___ O2
21. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) ___4__ Al + __3___ O2 =__2___ Al2O3
SUMMARY
1) Chemical reactions always involve the breaking of bonds, the forming of bonds, or both.
2)The Law of Conservation of Mass says that the same atoms must be the same before the chemical reaction and after the chemical reaction. They must also have the same mass.
3)To balance a chemical equation, you change the coefficient in front of each substance until there are the same number of each type of atom in both reactants and products.
In the final product, all of the same molecules are used as what we started with.
The same amount of molecules is not necessary for all of the molecules. They do not have to be balanced because if they are, they would make completely different compounds that what were needed. (example H2+O2 H2O. H4+O2=H2O This is now considered to be balanced because it shows us how many product and reactant will be present. Each atom in the reactant side will be present in the product side.)
The Law of Conservation of Mass: There can never be more or less atoms before the reaction as compared to after the reaction. This also means that it will have the same mass before and after the reaction.
Chemical reactions rearrange the atoms present.
Chemistry is the basis of almost all science and benefits thereof, without chemistry we would not have many of the wonderful things we have access to today, like normal milk, its pasteurized by a process that requires basic knowledge of chemistry.
CHEMICAL REACTIONS TUTORIAL QUESTIONS:
1. Starting materials in a chemical reaction are called reactants.
2. The ending materials in a chemical reaction are called products.
3. The arrow indicates a chemical change has taken place.
4. All reactions have one thing in common: there is a breaking, bonding, or both of chemical bonds.
5. Chemical reactions always involve broken old bonds, forming of new bonds, or both.
6. In all reactions we still have all of the atoms at the end that we had at the start.
7. In every reaction there can never be any more atoms or less atoms on one side than there are on the other.
8. Chemical reactions only balance in the atoms that are already there.
9. Let’s represent a reaction on paper. For example, hydrogen gas (H2) reacts with oxygen gas (O2) to form water
(H2O):
H2 + O2H2O
If we use only the atoms shown, we’d have 4 atoms of H and 3 atoms of O as reactants. This would make 2 molecule of H2O, but we’d have 1 atom of O leftover. However, this reaction only makes H2O.
Remember: reactions are not limited to 1 molecule each of reactants. We can use as many as we need to balance the chemical equation. A balanced chemical reaction shows:
a) What atoms are present before (in the reactants) and after (in the products)
b) How many of each reactant and product is present before and after.
10. So to make H2O from oxygen gas and hydrogen gas, the balanced equation would be:
___4_ H2 + ___2__ O2 ___=__ H2O Which is the same as: 2H2O
11. This idea is called the Law of Conservation of Mass
12. There must be the same coefficients and the same number of atoms before the reaction (in the reactants) and after the reaction (in the products).
| Element | # of atoms in Reactants | # of atoms in Products |
| H | 4 | 4 |
| O | 2 | 2 |
13. What is the balanced equation for this reaction?
__2__ Cu + ___1__ O2 =___2_ CuO
14. In the unbalanced equation there are:
Reactants Products
# Cu atoms __2___ = # Cu atoms ___2__
# O atoms ___2__= # O atoms ___2__
15. To balance this equation, we have to add __1____ molecules to the products, because this reaction doesn’t make lone __O___ atoms.
16. When we added a molecule of CuO, now the number of __Cu___ atoms is balanced but the number of _O___ atoms don’t match. Now we have to add more __O___ atoms to the reactants.
17. The balanced equation for this reaction is __2__ Cu + ___1__ O2 =__2__ CuO
This is the same thing as saying:
Reactants # Cu atoms __2___ = # O atoms ____2_ =
Products # Cu atoms ___2___ # O atoms ___2___
18. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) __1___ CH4 + __2___ O2= ___2__ H2O + __1___ CO2
19. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) __1___ N2 + __3___ H2 =___2__ NH3
20. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) ___2__ KClO3 = ____2_ KCl + __3___ O2
21. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) ___4__ Al + __3___ O2 =__2___ Al2O3
SUMMARY
1) Chemical reactions always involve the breaking of bonds, the forming of bonds, or both.
2)The Law of Conservation of Mass says that the same atoms must be the same before the chemical reaction and after the chemical reaction. They must also have the same mass.
3)To balance a chemical equation, you change the coefficient in front of each substance until there are the same number of each type of atom in both reactants and products.
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