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Science Clinic => Chemistry => Topic started by: Redwolflake15 on Nov 18, 2019

Title: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of water. ...
Post by: Redwolflake15 on Nov 18, 2019

Question 1

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water. The measured temperature decreased from 23.8 °C to 22.7 °C. Identify the unknown salt. The specific heat of water is 4.184 J g-1 °C-1, and assume the density of the solution is 1.00 g mL-1.
◦ NaNO3, D_rH = 20.50 kJ mol-1
◦ NaBr, D_rH = -0.60 kJ mol-1
◦ NaF, D_rH = 0.91 kJ mol-1
◦ LiBr∙2H2O, D_rH = -23.26 kJ mol-1
◦ LiNO3, D_rH = -2.51 kJ mol-1

Question 2

9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of water. The measured temperature increased from 23.4 °C to 24.7 °C. The specific heat of water is 4.184 J g-1 °C-1, and assume the density of the solution is 1.00 g mL-1. Calculate the molecular weight of the unknown solid if the D_rH was determined to be -2.51 kJ mol-1 via another experiment.
◦ 48 g mol-1
◦ 69 g mol-1
◦ 93 g mol-1
◦ 184 g mol-1
◦ 76 g mol-1

Title: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of water. ...
Post by: tuate on Nov 18, 2019

Answer 1

NaF, D_rH = 0.91 kJ mol-1

Answer 2

69 g mol-1

Title: Re: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of wat
Post by: Nia Daniels on Apr 15, 2020

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Title: Re: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of wat
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Title: Re: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of wat
Post by: Kenny Porter on May 27, 2020

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Title: Re: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of wat
Post by: john321123 on Jul 19, 2020

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Title: Re: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of wat
Post by: Andy Chen on Jul 19, 2020

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Title: Re: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of wat
Post by: chinaza ikeanyanwu on Apr 18, 2021

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Title: Re: 9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of wat
Post by: chloeeee22 on Jun 30, 2022

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