a) When the reaction takes place a yellow precipitate will be formed.
b) The law of conservation of mass is true.
<u>Explanation:</u>
a) When a lead nitrate solution is mixed with a potassium chromate solution, a yellow precipitate containing lead forms according to the equation:
→ 
b) Law of conservation of mass for the given reaction is true.
From the given table we know the mass of reactants and its products.
Law of conservation of mass is a principle when a reaction takes place in a closed system, the mass of the products and reactants in the system doesn't change.
⇒The sum of the mass of the reactants = The sum of the mass of the products.
The sum of the reactants = 128.71+128.97.
= 257.68 g.
The sum of the products = 154.10+103.58.
= 257.68 g.
Thus law of conservation of mass is true for the above reaction.
I think the correct answer would be D. The reaction that involves an acid and a covalent base would be the reaction of sulfuric acid and water or H2SO4 + 2H2O → 2H3O+ + SO42– . The acid would be H2SO4 and the covalent base would be H2O since it is being held by covalent bonds and when in solution it will have equal amounts of OH- and H+ ions.
Its C, Outermost Electrons.
M=n(pie)/RT
n=osmotic pressure(1.2 atm)
M=molar of the solution
R=gas constant(0.0821)
T= temperature in kelvin 25+273
M=[1.2atm /(0.0821L atm/k mol x 298k)]=0.049mol L
M= moles of the solute/ litres of solution(250/1000)
0.049= y/0.25
moles of solute is therefore =0.01225mol
molar mass=33.29 g/0.01225mol=2.7 x10^3g/mol
It’s is sodium, the 11th element on the periodic table.