We can define atomic mass the total of number of protons and number of neutrons in an atom or isotope.
<span>So when an isotope of yttrium has 39 protons and 59 neutrons, its atomic mass is equal to;
number of protons + number of neutrons = 39 + 59 = 98</span>
Explanation:
Reversible reactions that happen in a closed system eventually reach equilibrium. At equilibrium, the concentrations of reactants and products do not change. But the forward and reverse reactions have not stopped - they are still going on, and at the same rate as each other.
Answer:
Work done, W = 100 J
Explanation:
We have, Billy the friendly Robot uses 50 N of force to lift a box 2 meters in the air.
It is required to find the work done by Billy.
Work done by an object is given in terms of force and displacement. The formula used to find the work done is given by :

So, the work performed by Billy is 100 J.
Potassium hydroxide is a strong base and hydrobromic acid is a strong acid. This implies that the pH of the end-point [neutralization] of their titration will be around pH 7. A good indicator for this kind of pH is bromthymol blue. This is because this indicator changes its colour at pH 7.
Co2 = two covalent bonds
ccl4 = 4 covalent bonds
Lih = covalent bond