(3) both a chemical and a physical change can reach equilibrium. For example, an acid-base reaction can achieve equilibrium (chemical change), and a system can achieve dynamic equilibrium (phase changes from liquid to gas, for example), which is a physical change.
Unit of M is also mole/L, where mole is the moles of solute and L is the volume of the solution. The latter is given: 158 mL or 0.158 L. So we need to find out the moles of NH4Br.
Moles of NH4Br = Mass of NH4Br/molar mass of NH4Br = 17.0g/(14+1*4+79.9)g/mol = 0.1736 mole.
So, the molarity of the solution = 0.1736mole/0.158L = 1.10 mole/L = 1.10 M
Answer:
2HCI + Na2S ----> H2S + 2NaCl
Explanation:
For a balanced chemical equation, the number of moles of atoms on the reaction side must equal the number of moles of atoms on the product side, in accordance with the law of conservation of mass.
The correct answer is:
2HCI + Na2S ----> H2S + 2NaCl
Since it has equal number of moles of each atom on both sides of the equation: 2 atoms each of hydrogen, chlorine, and sodium on both sides of the equation as well as 1 atom of sulphur on both sides of the equation.
