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The student did another experiment using 20 cm3 of sodium hydroxide solution with a concentration of 0.18 mol/dm3 . Relative formula mass (Mr) of NaOH = 40 Calculate the mass of sodium hydroxide in 20 cm3 of this solution.

Answer= 0.144gWorking out:mol= conc x volume (in dm^3)mass = mol x RFFSo,mol = 0.18 x (20/1000) = 0.0036molMass= 0.036 x 40 = 0.144g

Answered by Celine Iswarya P. • Chemistry tutor

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ii) The maximum permitted sulfate concentration in water is 250mg dm^-3, 200cm^3 of aqueous BaCl2 is added to 300cm^3 of water at the maximum permitted sulfate level, and a white precipitate formed. Calculate the minimum conc. (mol dm^3)of the BaCl2

250x10^-3= 0.25g dm^-3sulfate mr x moles = mass0.25 x 3/10 = 0.075 g sulfatemr sulfare = 32 + (4 x 16) = 96moles sulfate = 0.075/96 = 7.8125 x10^-4Per equation above: moles SO₄

Answered by Josh M. • Chemistry tutor

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When aqueous barium chloride is added to a solution containing sulfate ions a white precipitate is formed. i)Write the ionic equation for the formation of this precipitate.

Ba²⁺_(aq)+SO₄^2-_(aq)---->BaSO_4(s)

Answered by Josh M. • Chemistry tutor

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What is bond polarity and why does it exist?

To understand bond polarity, you first must understand electronegativity. Electronegativity is the ability of the nucleus of any atom to attract electrons from another atom, it is dependant on the nuclear...

Answered by Catherine M. • Chemistry tutor

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Why is zinc not considered a transition metal?

The electron configuration of zinc is [Ar]4s²3d¹⁰. The only oxidative state which zinc has is Zn²⁺ in which its configuration is [Ar] (4s⁰⁾3d¹⁰, as t...

Answered by Niall S. • Chemistry tutor

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