A. K+, OH-
B. C6H5CO+, OH-
C. NH4+, Cl-
D. Mg++, 2 NO3-
Everything has 1 except for the Nitrate ion in D, which has 2
Answer: The element shown in the image is Helium (He).
Explanation: We are given a image of an atom having protons, neutrons and electrons.
Number of protons as shown in image = 2
Number of neutrons as shown in image = 2
Number of electron as shown in image = 2
Atomic number = Number of protons = Number of electrons
Atomic number of the element = 2
Atomic Mass = Number of protons + Number of neutrons
Atomic mass = 2 + 2 = 4
The element having Atomic number = 2 and mass number = 4 is Helium.
Element = 
It doesn't because pepper does not dissolve
Answer:
<h3>The answer is 8.29 %</h3>
Explanation:
The percentage error of a certain measurement can be found by using the formula

From the question
actual density = 19.30g/L
error = 20.9 - 19.3 = 1.6
We have

We have the final answer as
<h3>8.29 %</h3>
Hope this helps you