Answer:
A unit of mass used to express atomic and molecular weights, equal to one-twelfth of the mass of an atom of carbon-12. It is equal to approximately 1.66 x 10-27 kg.
Explanation:
0.075 L * 1.0 M = 0.075 mol HCl
H2 is half of HCl by the coefficients divide 0.075 by 2 and get 0.0375 mol H2 gas
Answer:
\frac{dh}{dt}_{h=2cm} =\frac{40}{9\pi}\frac{cm}{2}
Explanation:
Hello,
The suitable differential equation for this case is:

As we're looking for the change in height with respect to the time, we need a relationship to achieve such as:

Of course,
.
Now, since the volume of a cone is
and the ratio
or
, the volume becomes:

We proceed to its differentiation:

Then, we compute 

Finally, at h=2:

Best regards.
Answer:
A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.
Explanation:
Hello.
In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:

As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.
Best regards.