AN element is composed from atoms with the same number of protons,
A compound contain two or more different elements
Neither F2 nor Br2 are polar because they are nonpolar. It is a good rule of thumb to know that any diatomic molecules like F2 or Br2 are always going to be nonpolar. Another way to determine this is to use the acronym SNAP ( symmetrical=nonpolar, asymmetrical=polar). Since both F2 and Br2 are symmetrical molecules, they must be nonpolar.
I hope this helps.
Dark energy and dark matter seem over analyzed, although they are no different than gravity and wind. Dark energy can be the pulling caused by black holes, stars, and large planets. Dark matter also is just the effect of cosmic dust and debris pushed from explosions but also pulling caused by distant gravitational bodies.
Answer:
b. a new gas is observed in the form of bubbles
Explanation:
The only statement that was evidence of a chemical reaction is a new gas is observed in the form of bubbles Any time a new substance is created, a chemical reaction has taken place.
So half life is the time taken for a sample to decay to half its original mass, its a constant and applies to any original mass, it could be 5g or 1kg, it will take the same amount of time for the original mass to half. In this case the half life is 3 days.
After 3 days the sample will be at half its original mass, now 50g.
Now we can treat the 50g as if its a new sample. After another 3 days (6 days in total) there will be half of 50g left, = 25g.
