What do parentheses around a group of atoms in a chemical formula indicate?

Agas in a balloon at constant pressure has a volume of 160 ml at -125*c. what is its volume at 29.0*c?

The clouds are grey and ground is wet. a quantitative b qualitative

The following reaction shows the products when sulfuric acid and aluminum hydroxide react. al(oh)3 + h2so4 → al2(so4)3 + h2o the table shows the calculated amounts of reactants and products when the reaction was conducted in a laboratory. sulfuric acid aluminum hydroxide initial amount of reactant 40 g 15 g theoretical yield of water from reactant 14.69 g 10.38 g what is the approximate amount of the leftover reactant? 11.73 g of sulfuric acid 10.33 g of sulfuric acid 11.12 g of aluminum hydroxide 13.67 g of aluminum hydroxide