Answer:
C: object does not slide off the pan
Explanation:
What makes a question scientific is that we are able to test our hypothesis.
For example: Will increased sunlight cause more seeds to grow. We can test that simply by placing seeds in the sun and some out of the sun.
If you cannot test an hypothesis, then it is NOT scientific
For example: Macroevolution isn't a scientific question because we cannot test whether or not complex organisms come from simpler organisms. It can only be classified as an Hypothesis at best.
Answer:
The pH is 4.76
Explanation:
Step 1: Data given
Volume of a 0.476 M hydrocyanic acid solution = 29.8 mL = 0.0298 L
Volume of 0.487 M barium hydroxide solution = ?
Ka HCN = 6.2 * 10^-10
Step 2: Calculate pH
Hydrocyanic acid is a weak acid.
Barium hydroxide is a strong base.
The question asked = the pH BEFORE any base has been added, so we can ignore the base.
To calculate the pH of aweak acid, we need the pKa
HCN ⇔ H+ + CN-
Ka = [H+][CN-]/[HCN]
⇒ for weak acid: [H+]=[CN-]
Ka = [H+]²/[HCN]
[H+]² = [HCN]*Ka
[H+] = √([HCN]*Ka)
pH = -log(√([HCN]*Ka))
pH = -log(√(0.476 * 6.2*10^-10))
pH = 4.76
The pH is 4.76
