A student was given two clear liquids; a colorless liquid and a dark-blue liquid. The student was asked to combine the liquids i
n a beaker and record observations. Which of the following results, if true, would provide the best evidence that a chemical change took place when the liquids were combined? a. have combined to produce a new substance.
b. were pure substances before they were mixed.
c. are toxic and should be handled with extreme caution.
d. have been stored too long and are no longer good.
A chemical change is one in which a new substance is formed. To check if there is a chemical change when the two liquids were combined, what we simply need to do is to see if there is the formation of a new substance. The new substance formed is expected to be chemically and physically distinctive from its formative members.
B is incorrect
Being pure or impure does not provide any information if a chemical change had occurred or not.
C is incorrect
The toxicity of both doesn’t provide any information as regards if a chemical change had occurred or not
Recall; pH + pOH = 14 In this case [OH-] =0.100 m therefore; pOH = -LOG[OH-] = - Log (0.100) = 1.00 Therefore; the pOH is 1.00 And since, pH +pOH = 14 Then pH = 14-pOH = 14 -1 = 13 Thus the pH is 13.00
If Thomson's atomic theory was accurate, the positively charged particles would have gone through the foil. The balanced positive charges and negative charges within the atom would have made the atom neutral, and the positive charges would not have been concentrated enough to cause deflection.
The human eye can detect light at wavelengths between 400 to 900 nanometers. That is why we call this part of the electromagnetic spectrum visible light.