<span> red litmus paper turns </span>blue <span>under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F). Neutral litmus paper is purple.</span>
Answer:
The mass of coke needed to react completely with 1.0 ton of copper(II) oxide is 0.794 Ton.
Explanation:

1 Ton = 907185 grams
Mass of copper oxide = 1.0 Ton = 907185 grams
Moles of copper oxide =
According to reaction, 2 moles of copper oxide reacts with 1 mole of carbon.
Then 11403.95 moles of copper oxide will react with:
of carbon
Mass of 5,701.98 moles of carbon:

Mass of coke = x
Mass of carbon = 68,423.75 g
Percentage of carbon in coke = 95%


The mass of coke needed to react completely with 1.0 ton of copper(II) oxide is 0.794 Ton.
As we have the balanced reaction equation is:
N2O4 (g) ↔ 2NO2(g)
from this balanced equation, we can get the equilibrium constant expression
KC = [NO2]^2[N2O4]^1
from this expression, we can see that [NO2 ] is with 2 exponent of the stoichiometric and we can see that from the balanced equation as NO2
is 2NO2 in the balanced equation.
and [N2O4] is with 1 exponent of the stoichiometric and we can see that from the balanced equation as N2O4 is 1 N2O4 in the balanced equation.
∴ the correct exponent for N2O4 in the equilibrium constant expression is 1
One possible answer could be that a chemical reaction has occurred.