Here it says for a particular reaction, the change in its standard enthalpy equals negative 111.4 kilojoules and a standard change in entropy equals -25 joules over Kelvin. Here we need to calculate the standard change in our Gibbs free energy for this reaction at 298 Kelvin and it says what can be said about the spontaneity the reaction at this temperature.
So to calculate our change in a standard Gibbs free energy, we're going to say ΔG=ΔH-TΔS. Here we need to make sure the units are the same. One's in kilojoules, but one's in joules. Typically we have ΔG in kilojoules, so remember that one KJ is equal to 1000 joules, so this is equal to negative 0.025 kilojoules per Kelvin.
Here we plug these numbers in, so that's going to be -111.4 kilojoules -298 Kelvin times -.025 kilojoules over Kelvin. Kelvin's here cancel out, so our answer at the end will be in kilojoules. When we do that, we get -103.95 kilojoules, so the standard change in our Gibbs free energy here it is a value less than 0.
That means that it is spontaneous as written. Remember, if your ΔG is less than 0, it's going to be a spontaneous reaction.