Answer:
Three.
Explanation:
When counting the number of significant figures in a decimal number, you start counting from the right of the decimal point.
0
.00203
Counting from left to right from the decimal point , there are 5 digits.
However, the zeroes before any natural number is not counted as a significant figure.
0.00
203
Thus, there are
3
significant figures ie. 203.
Note: any other numbers added to the right of
0.00203
is also counted as a significant number.
eg.
0.002031
has 4 significant figures.
eg.
0.002030
has 4 significant figures.
Answer:
Even though the two substances possess many similarities, they have some unique properties. In turn, since they have the same properties, if they were the same substance, it would make matters worse, if the same chemical was in two different places, there would not be a difference between them since they are the same, just as it is with are two different chemicals would have differing properties since they are two properties would vary from one another since they are 2 totally different things!
When gasoline burns in a car engine, the burning is not used to move the car but is changed into heat.
Answer: Option B
<u>Explanation:</u>
Energy can be stored as kinetic and potential energy. As potential energy is the object's energy at rest. When gasoline is filled in car, then the car is attaining potential energy and as the gasoline is a chemical compound, the potential energy will be chemical potential energy.
The chemical potential energy releases energy on breakage of chemical bonds, so depending upon the strength of the bond, the energy will be released. Thus , in this case, the gasoline will burn on starting of the engine and the energy released from the burning of gasoline will be mostly changed to heat energy and some of them will be used for moving the car.
Answer:- 8.89 g of carbon dioxide can be produced.
Solution:- The balanced equation for the combustion of octane in presence of oxygen to give carbon dioxide and water is:
From given info, we have 6.9 g octane and 10.1 g oxygen and asked to calculate the maximum mass of carbon dioxide formed.
It is a stoichiometry problem. Let's first figure out the limiting reactant. For this we could either calculate grams of octane required to react completely with given grams of oxygen or vice versa.
From balanced equation, there is 25:2 mol ratio between oxygen and octane.
Let's say we calculate grams of oxygen for given grams of octane as:
= 24.1 g oxygen
From calculations, 24.1 g of oxygen are required to react completely with 6.9 g of octane but in actual only 10.1 g of oxygen are available. So, oxygen is limiting reactant and so the product yield depends on it and calculated as:
= 8.89 g carbon dioxide
So, from given masses of octane and oxygen, maximum 8.89 g of carbon dioxide can be produced.
