Answer: The precipitate formed is 
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid or precipitated form are represented by (s) after their chemical formulas.
A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.
The balanced chemical equation is:

Answer:
a. Plum pudding model
Explanation:
The plum pudding model of the atom was proposed by J.J. Thomson. It was the model he derived from his experiment on the gas discharge tube.
J.J Thomson was the first person to discover electrons which he called cathode rays because in the discharge tube, they emanate from the cathode.
- This led him to suggest the plum pudding model of the atom.
- The model reflects electrons being surrounded by a volume of negative charges.
I think it will be D or B but my mine answer is D
Answer:False
Explanation:co2 or carbon dioxide is a compound not an element, you can even check this on the periodic table
Answer:
19.8m/s
Explanation:
Given parameters:
Mass of the ball = 10kg
Height of the rail = 20m
Unknown:
Velocity at the bottom of the rail = ?
Solution:
The velocity at the bottom of the rail is its final velocity.
Using the appropriate motion equation, we can find this parameter;
V² = U² + 2gH
V is the final velocity
U is the initial velocity
g is the acceleration due to gravity
H is the height
the ball was rolled from rest, U = 0
V² = O² + 2 x 9.8 x 20
V = 19.8m/s