A chemical change is characterized of the formation of new substances or a chemical reaction. There are a number of observations that we can see if this type of change happens. One would be the formation of gas bubbles, this indicates that one of the products is a gas. Another observation would be a formation of a precipitate in the solution, it would indicate that the new solid formed is not soluble in the solution. A permanent color change in the solution would also indicate a chemical change because it may be that the new substance that is formed has its own distinct color when in solution.
Methane is the compound CH4, and burning it uses the reaction:
CH4 + O2 -> CO2 + H2O, which is rather exothermic. To find the heat released by burning a certain amount of the substance, you should look at the bond enthalpy of each compound, and then compare the values before and after the reaction. In methane, there are 4 C-H bonds, which have bond energy of 416 kj/mol, resulting in a total bond energy of 1664 kj/mol. O2 is 494 kj/mol. Therefore we have a total of 2080 kj/mol on the left side. On the right side we have CO2, which has 2 C=O bonds, each at 799 kj/mol each, resulting in 1598 kj/mol, and H2O has 2 O-H bonds, at 459kj/mol each, resulting in a total of 2516 kj/mol on the right hand side. Now, this may be confusing because the left hand side seems to have less heat than the right, but you just need to remember: making minus breaking, which results in a total change of 436kj/mol heat evolved.
Now it is a simple matter of find the mols of CH4 reacted, using n=m/mr.
n = 9.5/16.042 = 0.592195 mol
Therefore, if we reacted 0.592195 mol, and we produced 436 kj for one mol, the total amount of energy evolved was 436*<span>0.592195 kj, or 258.197 kj.</span>
Answer:
See below
Step-by-step explanation:
1. Colloid
B) Microscopic insoluble particles that are suspended throughout another substance.
Milk is a colloid. It consists of small fat globules suspended in water.
2. Emulsion
D) Two or more liquids that are not normally mixable.
Mayonnaise is an emulsion. It consists of oil, egg yolks, vinegar, and seasonings. Normally, the oil and vinegar (95 % water) do not mix. Without the egg yolk , they would quickly separate. Egg yolk contains the emulsifier, lecithin, which is attracted to both oil and water and stabilizes he mixture.
3. Solution
A) A solute that is evenly distributed within the solvent.
Sugar syrup is a solution of sugar in water.
4)Homogeneous
C) A mixture that has its components distributed evenly within the substance.
A homogeneous mixture has only one phase. For example, the sugar syrup is homogeneous, because, even with a powerful microscope, you can't see a boundary between the sugar particles and the water.
