# Tutor profile: Mike V.

## Questions

### Subject: Organic Chemistry

oh-ch2-ch-ch3-ch2-ch3 what is the iupac name?

For this problem, we want to find the longest chain with the Oh group in the highest priority. If we start with OH there is a 4 carbon chain which is butane. there is also a substituent carbon placed on the second carbon labeled as Ch3. this name would be 2 methyl butane. but since there is an alcohol we need to remove the e from butane and add on we also need to label where the oh group is located The answer to this is 2- methyl 1- butanol

### Subject: Chemistry

31.65 g of sodium chloride is added to 220.0 mL of water at 34 °C. How will this affect the freezing point of the water? Assume the sodium chloride completely dissociates in the water. Given: density of water at 35 °C = 0.994 g/mL Kf water = 1.86 °C kg/mol

For this question, we will use the formula deltaTemp=IKfm i= the vant Hoff factor kf= 1.86kg/mol m=molality of solution or mol solute divided my kg solvent the first step is to find the number of moles of NaCl the molar mass of NaCl is 58.44g we now divide our mass 31.65 by 58.44 which is .542 moles. now we will find the kg of water which is densityxvolume (.994g/ml)220ml(1kg/1000g)=.219kg molality= moles/kg solvent so..... .542moles/.219kg=2.477mol/kg i is the vant Hoff factor which is the number of ions in solution. NaCl has two ions in solution so i=2 now we enter all this into the equation deltatemp= 2(2.477)(1.86)=9.21 degrees Celsius

### Subject: DAT

200 mL of water is added to 55 mL of a 7.5-M solution of KOH. What is the final concentration of the solution? A) 10 M B) 13 M C) 0.08 M D) 6.5 M E) 1.6 M

This is a standard solution dilution problem. First, we will use the m1(v1)=m2(v2) formula. m1 is our initial concentration which is 7.5M. V1 is the initial volume which is 55ml We are trying to find M2, V2 is a final volume which will be 255ml because 200ml water is added to the 55ml KOH. Now we will input the values into he equation. (7.5M)(55ml)=(M2)(255ml) 413M/ml=255ml(m2) 413M/ml divided by 255ml is M2=1.6M

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