A. is decomposition so HCL = H2 + Cl2
not balanced cause hcl needs 2
2HCL = H2 + Cl2
balanced
b. Br2 + Al-i = AlBr3 + I2 single rep.
not balanced since br need 3 so watch carefully cause many changes needed
3Br2 + Al-i = AlBr3 + I2 not right is unbalanced so make it 2
3Br2 + Al-i = 2AlBr3 + I2 now left Al is unbal. so make 2 there
3Br2 + 2Ali = 2AlBr3 + I2
Balanced
C. Na + S = Na2S synthesis reaction is not bal. left Na needs 2
2Na + S = Na2S balanced.
Answer:
photons
Explanation:
Where,
n is the number of photons
h is Plank's constant having value
c is the speed of light having value
is the wavelength of the light
Given that, wavelength = 514 nm = 
Energy = 10.0 mJ = 0.01 J ( 1 mJ = 0.001 J )
Applying the values as:-

photons
I think is 1 and a half km
Answer:
The answer to your question is below
Explanation:
Polyatomic ions are ions composed for more than 1 atom. There are polyanions and polycations.
Polyanions have a negative charge and polycations have a positive charge.
Examples
Polyanions Polycations
acetate CH₃COO⁻ ammonium NH₄⁺¹
bromate BrO₃⁻
chlorate ClO₃⁻
hydroxide OH⁻
nitrate NO₃⁻
nitrite NO₂⁻
sulfate SO₄⁻²
phosphate PO₄⁻³
permanganate MnO₄⁻
We write parentheses before or after a polyatomic ion to emphasize that the oxidation number of the atom which interacts with it affects all the atoms that form part of the polyatomic ion.