Chemistry Answers

The amount of iron in a meteorite is determined by a redox titration using KMnO4 as the titrant. A 0.4185-g sample is dissolved in acid and the liberated Fe3+ quantitatively reduced to Fe2+ using a Walden reductor. Titrating with 0.02500 M KMnO4 requires 41.27 mL to reach the endpoint. Determine the %w/w Fe2O3 in the sample of meteorite.

A 250.0-mg sample of an organic weak acid is dissolved in an appropriate solvent and titrated with 0.0556 M NaOH, requiring 32.58 mL to reach the end point. Determine the compound’s equivalent weight.

how to prepare a 5moldm^-3 HCl solution from 12moldm^-3 and 2moldm^-3 HCl solution

Which of the following statements pertaining to an SN2 reaction is INCORRECT? (1) The nucleophile attacks the carbon from the side of the molecule opposite the group being displaced, that is, opposite to the leaving group. (2) The rate of the reaction is dependent of the concentration of the nucleophile. (3) The reaction proceeds with simultaneous bond formation and bond breaking. (4) Bulky groups around the reaction site speeds up the reaction.  

Alkyl halides can undergo nucleophilic substitution reactions. Which of the following statements is CORRECT? (1) The second order nucleophilic substitution reactions involve inversion of configuration at the central atom. (2) Tertiary alkyl halides are unlikely to undergo SN1 type reactions. (3) Unless resonance stabilization is observed, primary alkyl halides are unlikely to undergo second order nucleophilic substitution. (4) The strength of the nucleophile does not play a role in the order of the nucleophilic substitution reaction. 

Which of the following reactions will NOT take place?  (1)  CH3CH2CH2BrNaN3ethanol -waterCH3CH2CH2N3 (2)  CH3CH2CH2BrNaIacetoneCH3CH2CH2I (3)  CH3CH2CH2BrCH3CH2CH2CH3NaSCH3 (4)  CH3CH2CH2BrCH3CH2CH2OCCH3OCH3CONaO

at standard temperature and pressure one mole of gas occupies a volume on 22.415dm³ , exert a pressure of one atmosphere at 0°c . Calculate the molar gas constant

What is the concentration of hydronium ions in a solution which is 0.5M with respect to nitrous acid and 0.65M with respect to sodium nitrite. Assume that sodium nitrite is completely ionized?

What is the concentration of ammonia which reacts with water to produce ions to the extent of 1.98 percent. Ionization constant of ammonia=1.81×10^-5

Giving reasons arrange the following in increasing order of their vO-H frequency: ethanol, trichloroacetic acid, acetic acid and chloroacetic acid