When 2.5g of NaOH were dissolved in 49.0g water in a calorimeter at 24.0 C, the temperature of the solution went up to 37.1 C.
a. Is the solution reaction exothermic?
Why? The temperature or the water went from 24.0 to 37.1 which is an increase. If the solution of NaOH in water made the temperature of the water go up, do you think the NaOH + H2O gave off heat (exothermic) or took in heat (endothermic)?
b. Calculate q h2o, using eq. 1. Its tough to know what you did when you don't supply equation 1.
c. Find delta H for the reaction as it occured in the calorimeter (eq. 5).See comment to part b.
d. Find delta H for the solution of 1.00g NaOH in water. The delta H you found was for 2.5g. What would it be for 1.0g?
Find delta H for the solution of 1 mole NaOH in water. The delta H you found for part d was for 1.0g. A mol of NaOH is 40g. Just convert from 1.0g to 40g.
f. given that NaOH exists as Na+ and OH- ions in solution, write the equation for the reaction that occurs when NaOH is dissolved in water. NaOH(s) ==> Na+(aq) + OH-(aq) + heat
g. Using ethalpies of formation as given in thermodynamic tables, calculate delta H for the reaction in part f and compare your answer with the result obtained in Part e. You must look up the delta Hf.
Please explain how to do. All of this is new to me. Thank you so much!
When 2.5g of NaOH were dissolved in 49.0g water in a calorimeter at 24.0 C, the temperature of the solution went up to 37.1 C.
a. Is the solution reaction exothermic?
Why?
b. Calculate q h2o, using eq. 1.
c. Find delta H for the reaction as it occured in the calorimeter (eq. 5).
d. Find delta H for the solution of 1.00g NaOH in water.
Find delta H for the solution of 1 mole NaOH in water.
f. given that NaOH exists as Na+ and OH- ions in solution, write the equation for the reaction that occurs when NaOH is dissolved in water.
g. Using ethalpies of formation as given in thermodynamic tables, calculate delta H for the reaction in part f and compare your answer with the result obtained in Part e.
a. Is the solution reaction exothermic?
Why?
Yes, the solution reaction is exothermic. When the temperature of water increases, it indicates that heat is being released. Since the temperature of the water went up when NaOH was dissolved in it, it means that the NaOH + H2O reaction gave off heat, making it exothermic.
b. Calculate q h2o, using eq. 1.
I'm sorry, but you haven't provided equation 1, so I can't calculate q h2o for you. However, I can tell you that q h2o represents the heat gained or lost by water in a reaction.
c. Find delta H for the reaction as it occurred in the calorimeter (eq. 5).
You haven't mentioned equation 5, so I can't provide you with the delta H for the reaction. Delta H represents the change in enthalpy in a reaction.
d. Find delta H for the solution of 1.00g NaOH in water.
Find delta H for the solution of 1 mole NaOH in water.
To find delta H for 1.00g NaOH in water, you can use the ratio of 2.5g NaOH to the change in temperature (37.1 - 24.0) to find the heat released. However, it's important to note that the delta H you found was for 2.5g, so you may need to adjust it for 1.00g. Similarly, to find delta H for 1 mole NaOH in water, you would need to adjust the heat released per gram to the heat released per mole by converting the mass from grams to moles (using the molar mass of NaOH, which is 40g/mol).
f. given that NaOH exists as Na+ and OH- ions in solution, write the equation for the reaction that occurs when NaOH is dissolved in water.
NaOH(s) + H2O(l) → Na+(aq) + OH-(aq) + heat
g. Using enthalpies of formation as given in thermodynamic tables, calculate delta H for the reaction in part f and compare your answer with the result obtained in Part e.
To calculate delta H using enthalpies of formation, you would need to look up the enthalpies of formation for Na+(aq) and OH-(aq) ions, as well as NaOH(s), in thermodynamic tables. Then you can subtract the sum of the enthalpies of formation of the reactants from the sum of the enthalpies of formation of the products to find the delta H for the reaction. Comparing this result with the previous answer obtained in part e will help you determine if they are in agreement. Remember, the values obtained from thermodynamic tables might be more accurate.
a. To determine whether the solution reaction is exothermic, we can look at the change in temperature. In this case, the temperature of the water increased from 24.0°C to 37.1°C. Since the temperature is increasing, it means that heat is being released by the reaction. Therefore, the solution reaction is exothermic.
b. Equation 1 is missing, so we cannot calculate q h2o without it. Please provide equation 1.
c. Similarly, without equation 5, we cannot calculate delta H for the reaction as it occurred in the calorimeter. Please provide equation 5.
d. To find delta H for the solution of 1.00g NaOH in water, we need to determine the delta H for 2.5g first. Then, we can use that value to find delta H for 1.00g.
e. To find delta H for the solution of 1 mole NaOH in water, we can use the delta H value we found for 1.00g NaOH and convert it to moles. Since the molar mass of NaOH is 40g/mol, we can assume that 1.00g NaOH is equivalent to 0.025 moles. Therefore, we would multiply the delta H value for 1.00g by a factor of 0.025 to obtain the delta H for 1 mole NaOH.
f. The equation for the reaction that occurs when NaOH is dissolved in water is:
NaOH (s) + H2O(l) → Na+(aq) + OH-(aq) + heat
g. To calculate delta H for the reaction in part f using enthalpies of formation, we would need to look up the delta Hf values for each species involved in the reaction (NaOH, Na+, OH-, H2O). By subtracting the sum of the delta Hf values of the reactants from the sum of the delta Hf values of the products, we can calculate the overall delta H for the reaction. Then, we can compare this value with the result obtained in part e to see if they match.
a. To determine if the solution reaction is exothermic or endothermic, you need to consider the change in temperature. In this case, the temperature of the water increased from 24.0°C to 37.1°C. Since the temperature increased, it indicates that heat was released. Therefore, the solution reaction is exothermic.
b. To calculate q H2O, which represents the heat absorbed or released by water, you can use the equation:
q H2O = m H2O * c H2O * ΔT
Where:
- m H2O is the mass of water (49.0g)
- c H2O is the specific heat capacity of water (4.18 J/g°C)
- ΔT is the change in temperature (37.1°C - 24.0°C)
Substituting the values, you can calculate q H2O.
c. The delta H for the reaction as it occurred in the calorimeter can be determined using equation 5. It is not clear what equation 5 refers to, so you would need to provide that equation or refer to a specific reaction or process.
d. To find delta H for the solution of 1.00g NaOH in water, you can use the information obtained for the reaction with 2.5g of NaOH. Since the reaction with 2.5g of NaOH resulted in a certain delta H, you can use this ratio to determine the delta H for 1.00g of NaOH.
e. Similarly, to find delta H for the solution of 1 mole of NaOH in water, you can use the information obtained for the reaction with 2.5g of NaOH. Since the molar mass of NaOH is 40.0 g/mol, you can use this ratio to determine the delta H for 1 mole of NaOH.
f. The equation for the reaction that occurs when NaOH is dissolved in water can be written as:
NaOH(s) + H2O(l) → Na+(aq) + OH-(aq) + heat
g. To calculate delta H for the reaction using enthalpies of formation, you will need to look up the specific values for the enthalpies of formation of the reactants and products involved in the reaction. Then, you can use the enthalpy of formation values to calculate the overall delta H for the reaction. By comparing this with the result obtained in part e, you can determine if they agree or not.