In late 18th century, people wore rubber soled shoes called plimsolls, but they weren't the best sneakers. Around 1892, a US company named Keds started sneakers with a canvas top and rubber soles. By 1917, these were mass produced.
Answer:
The mass was there all along, it was just in the air. The weight of the oxygen from the air is not weighed in the beginning, only at the end as part of the product, making it seem like there is a total mass change.
Answer:
a) a = 3485 M⁻¹cm⁻¹
b) C = 0,000127 M
Explanation:
Lambert-Beer law says that there is a linear relationship between absorbance and concentration of a chemical substance. The formula is:
A = a×b×C
Where A is absorbance, a is molar absorptivity, b is path length and C is concentration.
a) In the problem Concentration is 0.0000792 M, b is 1,000cm and Absorbance is absorbance of sample-absorbance of blank: 0,341-0,065 = 0,276
Replacing:
0,276 = a×1,000cm×0,0000792M
<em>a = 3485 M⁻¹cm⁻¹</em>
b) As the experiment consist in the same compound in the same solvent, the molar absorptivity will be the same, a = 3485 M⁻¹cm⁻¹, path length will be 1,000cm and absorbance: 0,508-0,065 = 0,443
Replacing:
0,443 = 3485 M⁻¹cm⁻¹×1,000cm×C
<em>C = 0,000127 M </em>
<em></em>
I hope it helps!
I believe it is b electric energy etc...
Answer: Gases are complicated. They're full of billions and billions of energetic gas molecules that can collide and possibly interact with each other. Since it's hard to exactly describe a real gas, people created the concept of an Ideal gas as an approximation that helps us model and predict the behavior of real gases. The term ideal gas refers to a hypothetical gas composed of molecules which follow a few rules:
Ideal gas molecules do not attract or repel each other. The only interaction between ideal gas molecules would be an elastic collision upon impact with each other or an elastic collision with the walls of the container. [What is an elastic collision?]
Ideal gas molecules themselves take up no volume. The gas takes up volume since the molecules expand into a large region of space, but the Ideal gas molecules are approximated as point particles that have no volume in and of themselves.
If this sounds too ideal to be true, you're right. There are no gases that are exactly ideal, but there are plenty of gases that are close enough that the concept of an ideal gas is an extremely useful approximation for many situations. In fact, for temperatures near room temperature and pressures near atmospheric pressure, many of the gases we care about are very nearly ideal.
If the pressure of the gas is too large (e.g. hundreds of times larger than atmospheric pressure), or the temperature is too low (e.g.
−
200
C
−200 Cminus, 200, start text, space, C, end text) there can be significant deviations from the ideal gas law.
Explanation:
