Energetics

The energy level diagram for the reaction between magnesium and hydrochloric acid is shown.

• Energy is given out during the reaction

• The products are at a lower energy level than the reactants

• The reaction is endothermic.

Tags

NGSS.HS-PS1-4

Which statements about exothermic and endothermic reactions are correct?

• During an exothermic reaction, heat is given out

• The temperature of an endothermic reaction goes up because heat is taken in

• Burning methane in the air is an exothermic reaction

Tags

NGSS.HS-PS1-4

endothermic reactions ........

• have more energy in their products

• have less energy in their products

• have more energy in their reactants

• have the same amount of energy in reactants and products

Tags

NGSS.HS-PS1-4

A minus figure in an enthalpy change is....

• a mistake

• sometimes caused by the wrong reactants

• no significance

• tells you it is an exothermic reaction

Tags

NGSS.HS-PS1-4

The amount of energy change in a reaction is known as.....

• endothermic

• Delta H

• exothermic

• Mole/Mass/delta H

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

A 100ml of water is heated by the burning of a biscuit.If he ΔT=20⁰C and the change in mass of the biscuit, Δm =1.35g.Find the heat of the process in kJ/g. (Q=mcΔT)

• 6.19

• 61.9

• 6193

• 8360

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

H₂ + ½ O₂ --> H₂O + 285kJ is an example of a(n)

• Electrical equation
• Heat equation
• Thermochemical equation

Tags

NGSS.HS-PS1-4

C+ O₂ --> CO₂ + 60kJ, what is the value for ΔH for the reaction?

• +60
• -60
• there is no way to know

Tags

NGSS.HS-PS3-1

which of the following enthalpy changes represent the enthalpy change of formation?

• Mg(s) + Cl₂(g) → MgCl₂(s)

• Mg²⁺(g) + 2 Cl ^-(g) → MgCl₂(aq)

• O2(g) → 2 O(g)

• 2Mg (s) + O₂(g) → 2MgO(S)

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Describe the energy change that takes place when bonds are made.

• a) Energy is given out
• b) Energy is taken in
• c) Energy is taken in and then given out
• d) Energy is given out and then taken in

Tags

NGSS.HS-PS1-4