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The balanced chemical equation for the rusting of iron is the following:
4 Fe + 3 O₂ → 2Fe₂O₃
The coefficients to balance the equation are 4,3,2. The fundament of this balance is the Law of Conservation of Mass. This Law states that matter is neither created nor destroyed in a chemical reaction, and in a chemical equation, the moles of each atom is conserved in both sides of the arrow. That means that if 4 Fe atoms are on the left side, 4 Fe atoms should be on the right side.
A suggestion for balancing equations is to start with metal atoms, continuing with non-metals, then hydrogen and lastly oxygen.
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Answer:

Explanation:
Na reacts with all OH groups to produce hydrogen.
The reaction with cyclobutanol is shown below.
The reaction with butanoic acid is

Both compounds release bubbles of hydrogen, so you can't use sodium to distinguish between them.
The answer Is D due to the fact the car is the heaviest one on there and would require the greates amount of force to move
Answer: The ratio of atoms in calcium bicarbonate ; Ca : H : C : O = 1:2:2:6.
The ratio of atoms in lithium sulfide; Li : S = 2 : 1
Explanation:
In calcium bicarbonate:
In a molecular formula of calcium carbonate there are:
Number of Calcium atoms = 1
Number of Hydrogen atom = 1 × 2 = 2
Number of Carbon atoms = 1 × 2 = 2
Number of Oxygen atoms = 3 × 2 = 6
So, Ca : H : C : O = 1 : 2 : 2 : 6
In lithium sulfide :
In a molecular formula of lithium sulfide there are:
Number of Lithium atoms = 1 × 2 = 2
Number of Sulfur atoms = 1
So, the Li : S = 2 : 1
Answer: Option (D) is the correct answer.
Explanation:
- A pure substance is defined as the substance that is made up of only one type of atom or only one type of molecule.
For example,
is a molecule and it is a pure substance.
Also, substances that contain two or more different element which are chemically combined in a fixed ratio by mass are known as compounds. They are also pure substances.
A pure substance can only be separated by a chemical method and not by any physical method.
- A heterogeneous mixture is defined as the mixture which contains non-uniform composition of solute particles into the solution.
For example, mud dissolved in water.
It is not necessary that two or more substance present in a heterogeneous mixture should be of same phase.
Also, it is not necessary that combination of a liquid and a solid always results in a heterogeneous mixture.
If the solid is able to dissolve completely into the liquid then it will result in a homogeneous mixture.
- Whereas a homogeneous mixture is defined as the mixture which contains uniform distribution of solute particles into the solvent.
For example, salt dissolved in water is a homogeneous mixture.
Thus, we can conclude that the statement composition is uniform throughout a homogeneous mixture, is correct.