How to tell if a reaction is endothermic or exothermic by looking at it?

Imagine if you are given a mystery element

In whare atoms in group 1 and atoms in group 18 different? metals nonmetals noble gases metalloids

Why is hydrogen the most common element in the universe?

What is the molality of a solution that has 3 mol of glucose in 6 kg of water?

What changes increases the pressure in a gaseous system?

What is a scientific explanation for a range of hypotheses and observations supported by testing

A chemical reaction involves the rearrangement of atoms to form new molecules. During a chemical reaction, however, atoms are neither created nor destroyed. Which of the following is true about the atoms involved in a chemical reaction? A.

What is the new concentration, after diluting 300 mL of a 1.5 M LiCl solution to 1L

The answer that he gave was wrong

In which orbital does an electron in a bromine atom experience the smallest?