D. 2Na (s) + MgF2 → 2NaF (s) + Mg (s)
Explanation:
From the given choices, 2Na (s) + MgF2 → 2NaF (s) + Mg (s) is balanced
A balanced equation is one that obeys the law of conservation of matter which states that "matter is neither created nor destroyed but transformed from one form to another".
We expect to find the same name of atoms on both sides of the equation.
let us examine the choices;
Zn (s) + HCl (g) → ZnCl2 (s) + H2 (g)
Reactants Products
Zn 1 1
H 1 2
Cl 1 2
Na (s) + O2 (g) → Na2O
Reactants products
Na 1 2
O 2 1
Na (s) + MgF2 → 2NaF (s) + Mg (s)
Reactants products
Na 1 2
Mg 1 1
F 2 2
2Na (s) + MgF2 → 2NaF (s) + Mg (s)
Reactants products
Na 2 2
Mg 1 1
F 2 2
learn more:
Balanced equation brainly.com/question/2947744
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Answer:
Average speed = 13.5 m/s
Explanation:
Since the car is running at a speed of 27 m/s and it stops after 3 seconds by applying the brake. Therefore, the initial speed of the 27 m/s and final speed is 0.
Use below formula to find the average speed :
Average speed = (Initial speed + final speed ) / 2
Average speed = (27 + 0 ) / 2
Average speed = 13.5 m/s
