Answer:
Oxygen is the most contain in earth but you asked in a,b,c and d. So I'll choice A. aluminium.
The correct answer is d) chrima
Answer:
Explanation:
To find the mass percent composition of an element, divide the mass contribution of the element by the total molecular mass. This number must then be multiplied by 100% to be expressed as a percent.
Answer:
The pH of the sample is 3,4.
Explanation:
We calculate the pOH from the formula pOH = -log (OH-). We know that for all aqueous solutions: pH + pOH = 14, and from there we clear pH:
pOH= -log (OH-)=10,60
pH + pOH = 14
pH + 10,60 = 14
pH=14 -10,60
<em>pH=3,4</em>
<span>H2CO3 <---> H+ + HCO3-
NaHCO3 <---> Na+ + HCO3-
When acid is added in the buffer, the excess H+ of that acid reacts with HCO3- to form H2CO3, and due to this NaHCO3 dissociates into HCO3- to attain the equilibrium. and hence there is no net effect of H+ due to pH remain almost constant.
when a base is added to the buffer, the OH- ion of base react eith H+ ion present in buffer, then to attain equilibrium of H+ ion, the H2CO3 dissociates to produce H+ ion, but now there is the excess of HCO3- due to which Na+ ion react with them to attain equilibrium of HCO3-. hence there is again no net change in H+ ion due to which pH remain constant.....</span>
