Help with Lab calculations Explain please Before heating Mass of empty tube (g)

Question

Help with Lab calculations Explain please
Before heating Mass of empty tube (g) 18.436 Mass of test tube and mixture before heating 21.28 g
First heating Mass of test tube and mixture after first heating 20.876 Volume of water displaced mL 254 Barometric pressure mm Hg 726 Temp 22.1 c Vapor pressure at this temp 20.7 torrs
After second heating Mass of test tube and mix 20.793 Water displaced 117 mL Show your work for Trial One in the space provided below. . For BOTH trial one and two create and ottach an excel spreadsheet for the following calculations: o Include a completed dota sheet AND a second with Show Formulas' active (Click on Formulas' tab, select Show Formulas" in the "Formula Auditing" subsection. Co ar Hey mess vatue uuld Calculate the mass of oxygen evolved during each heating uTT&oren;) Calculate the number of moles of molecular oxygen evolved during each heating (trial). 0 / ywel 32.00 1 Calculate the partial pressure of the oxygen in the flask using the atmospheric pressure and the water vapor pressure. PPi a o Calculate the volume number of moles each oxygen sample. ( V3- of one mole of oxygen under laboratory conditions using a ratio including the volume and Va Vouwetmbl dA n fom sef

Explanation / Answer

1) To calculate the mass of O2 evolved during each heating

First trial,

mass of O2 = mass of test tube and mix before heating –mass of test tube and mix after first heating=21.28g-20.876g=0.404 g

second trial,

mass of O2 = mass of test tube and mix before heating –mass of test tube and mix after first heating=21.28g-20.793g=0.487 g

2)moles of O2 released after first trial= mass of o2 released/molar mass of O2=0.404g/32g/mol=0.0126 moles

moles of O2 released after second trial= mass of o2 released/molar mass of O2=0.487g/32g/mol=0.0152moles

3)Patm=po2+p(H2O)

P(h2O ) at 22.1C=19.956 torr (refer table)

Patm=726 mmhg=726 torr

pO2=patm-pH2O=726 torr-19.956 torr=706.044 torr

4)molar volume of O2=volume/moles of o2

First trial , molar volume=254ml (water displaced)/ 0.0126 moles=0.254L/0.0126 moles=20.158 L/mol

4)determine volume of O2 at STP

P1 *V1/T1=constant

So P(STP)* V(STP)/T(STP)= P(lab)* V(lab)/T(lab)

T(STP)=22.1C=273+22.1=295.1 k

V(STP)=P(lab)* V(lab)/T(lab) *T(STP)/P(STP)

           =706.044 torr*254ml/295.1 k * 273K/760 torr=218.296 ml= 0.2183L

Molar volume at STP=0.2183L/0.0126 moles=17.325 L/mol

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