Answer:
No, it's a physical reaction.
Explanation:
A chemical change produces new chemical compounds, but combining water and powder is just mixing the powder with the water. It's not a new compound.
I don't know how to really explain, sorry :)
Answer:
Ground state
the state with the smallest amount of energy.
Answer:
Explanation:
<u>Problem</u>:
In a gender based experiment, the blood pressure of different ages of men is been checked and recorded to determine if there is any correlation. What will be the independent, dependent and controlled variables?
<u>Answer</u>:
A controlled variable is the variable that is left constant throughout the course of an experiment. The controlled variable here is the gender.
A dependent variable is the variable that is been determined or measured during the course of an experiment. The dependent variable here is the blood pressure.
An independent variable is the variable that is intentionally or decidedly altered during the course of an experiment. The independent variable here is the age.
<span>The reason it will be 7 for some titrations is that when you titrates a strong acid with a strong base for example HCl and NaOH the salt formed is conjugate base of strong acid and will be a very weak base
That means that it cannot produce any OH^-1 and all the H+ has been converted to water.The only source of H+ or OH is water with a Ka of 10^-14 so the pH = -log [H+]=-log 10^-7 = 7
second reason is
When you titrates a weak acid with strong base at equivalence point
only a water solution of the conjugate base exists
CH3COOH + NaOH ----- Na+ CH3COO^-1 + H2O
Since the conjugate base is the conjugate base of a weak acid it will hydrolyze in water like so
for instance Na+ CH3COO^-1 + HCl---- CH3COOH + NaCl the equivalence point will be way BELOW 7 and in the case of above will be less than 5. So pH of 7 at equivalence point is only reached in strong acid strong base titrations.
hope this helps</span>
