Pretty sure it's D. El Nino but not positive.
Frequency is defined as the number of waves per second. In this machine 25 waves pass in one second.
We need to calculate the number of waves that pass a particular point during one second.
During 2 seconds -25 waves
Therefore in one second - 25/2 = 12.5 waves/s.
1 wave per second has the unit Hertz (Hz)
Therefore answer is 12.5 Hz
Answer:
1) chemical indicators won't work above it's pH range so therefore it probably won't change colour.
2) the solution should be clear and colourless to see colour change.
3) indicators tend to be of low accuracy so it's not 100% reliable.
The answer is D, medical diagnosis
Missing question:
<span>(1) C2H5OH (3) C12H22O11
(2) C6H12O6 (4) CH3COOH.
Answer is: 4) CH</span>₃COOH, acetic acid.
In water, acetic acid dissociates on ions, so it can conduct electricity:
CH₃COOH(aq) ⇄ CH₃COO⁻(aq) + H⁺(aq).
When we put
electrodes (cathode and anode) in acetic acid solution, positive and negative
ions migrate to electrodes.<span>
Negative acetate ions go to positive electrode
and gives electrons to electrode.
<span>Positive hydrogen ions go to negative electrode
and gain electrons.</span></span>
