A method of procedure that has characterized natural sciences the 17th century, consisting in systematic observation, measurement, and experiments, and the formulation, testing, and modification of hypotheses.
.
the answer is Yes, a hydrocarbon is any compound that contains hydrogen and oxygen.
The answer is (4), (3) is merely a change in composition, thus not chemical but physical.
Answer: (4). Option 4 seems to be the one undergoing a chemical change because there is a formation gas from the bubbling that occurs. Chemical change is the change that results to the formation of a new substance. The other options given are examples of physical change.
Answer:
The value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.
Explanation:
The value of gas constant is 0.0821.
We know that, the ideal gas law is as follows :

Where
P is pressure
V is volume
T is temperature
In order to use the Ideal Gas Constant of 0.0821, the units are follows :
Volume = Litre (L)
Pressure = atm
Amount = mol⁻¹
Temperature = K⁻¹
So, the value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.