Molarity is defined as the number of moles of solute in 1 L of solution
the mass of Ca(NO₃)₂ present - 8.50 g
therefore number of moles of Ca(NO₃)₂ - 8.50 g / 164 g/mol = 0.0518 mol
the volume of solution prepared is 755 mL
therefore if there are 0.0518 mol in 755 mL
then in 1000 mL the number of moles - 0.0518 mol / 0.755 L
molarity is therefore - 0.0686 M
All the answers are on the actual periodic table. You should never be told to remember it so I think this is a recourse you are allowed to look at whilst doing your homework lol :) all the answers are written on it hope it helps
Answer:
B) the chemicals are gaining energy from the surroundings.
Explanation:
The positive sign of the energy difference in a chemical reaction would indicate that the chemicals are gaining energy from the surroundings. This is what happens in an endothermic reaction.
In an endothermic reaction, heat is absorbed from the surroundings hence the surrounding becomes colder at the end of the changes.
- Here the energy change is assigned a positive value.
- This is because the heat energy level of the final state is higher than that of the initial state.
- So, the difference gives a positive value.
