what can i do with powdered ground mustard?

I had to buy a bottle of powdered ground mustard for a recipe I made. What else can I use it for besides mac n cheese and a breakfast casserole?

What will happen in my recipe that calls for mustard seed if I used ground mustard instead?

I have a coleslaw recipe that calls for both celery seed and mustard seed. I can only find ground mustard but I found the celery seed. Will the ground mustard make the salad taste too strong? Should Ikeep looking for mustard seed or just cut in half the amount called for?

I have 2 burning bushes. There is yellow mustard like stuff on the ground by them. What is it?

It does look like a dog was sick, that is what I thought at first that the dog was sick but then realized that he wont go by the bushes.

I have a recipe for crushed brown mustard seed. Can I substitute “ground mustard” instead?

I couldn’t find “brown mustard seed” anywhere. Can I substitute ground mustard instead?