Why do sidewalks have built in cracks every few feet

7. what temperature is need to just dissolve 50 g of nh4cl in 75 g of water? '

The diagram below shows a cell placed in a solution.a cell is shown placed inside a beaker. it is labeled cell. the solution inside the beaker is labeled 40% salt solution and the solution inside the cell is labeled 20% salt solution.only water is allowed to move in and out of the cell. what will most likely happen to the cell? it will expand as water moves out of it. it will shrink as water moves out of it.it will expand as water moves into it. it will shrink as water moves into it.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation: