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Agreed.

Wouldn't it be 1 sf? They said "10mL ethanol" where that is clearly 1 sf. I got that too. I got 1.397 first (not sure if it exactly was this) and found i didn't recalculate the concentration, and changed it to 2.397.

I thought all of them were wrong in 12.. I picked (B) though.

I'm not too sure lol. I just used what the question gave.

Let lemon juice be represented by the chemical formula H3X 3NaOH + H3X -> Na3X + 3H2O n(NaOH) = 0.550 x 0.0295 = 0.016225 moles n(NaOH) : n(H3X) = 3:1 .'. n(H3X) = 0.016225 /3 = 5.408 x 10^(-3) moles m(H3X) = 5.408 x 10^(-3) x 192.12 = 1.039049 grams .'. [H3X] = 1.039049/25 = 4.16% (g/mL) (3 sf)

It's just you.

1. The hydrochloric acid is in the burette. 2. First finding moles of base neutralising the HCl, n(HCl) = 0.0244 x 0.1 = 0.00244 moles n(HCl):n(NaX) = 1:1 .'. n(NaX) = 0.00244 moles in a 20mL sample .'. n(NaX) = 0.00244 x 5 = 0.0122 moles in a 100mL sample n = m/MM 0.0122 = (1)/(MM) MM =...

Moles of H2 produced = 4.68/24.79 = .1888 n(H2):n(H2O) = 1:2 .'. n(H2O) used = .1888 x 2 = .3776 Volume remaining = 1200 - .3776 x (1.008 x 2 + 16) = 1193.2mL = 1.1932L n(H2):n(NaOH) = 1:2 n(NaOH) = 0.3776 .'. n(OH-) = 0.3776 [OH-] = 0.3776/1.1932 = .31644 pOH = -log(.31644) = .49971 pH + pOH =...

You get that if you just find the moles of NaOH produced and then using pOH = -log[OH] immediately. What you need to take in to account is the decrease in H2O because it reacts, then finding the new volume, and then the [OH-] and proceed from there.

Agreed with Aysce for 4U Maths! Physics - In2Physics & Jacaranda I was just looking through In2Physics its so colourful and nice lol.

ln(\frac{x}{x^2 + 1}) = lnx - ln(x^2 + 1) Easier to differentiate

I feel for you as someone who shares the same subjects and has the same problem.

study is going okay. i've reached a point where i don't want to look at another past paper lol just going to look over notes. you?

Some maglev trains employ electrodynamic suspension (EDS) which involves the use of electromagnets and superconductors. Electromagnets are placed across train tracks and are powered by three-phase AC current to produce a dynamic magnetic field, interacting with the superconductors at the bottom...

1. The ratio of vertical acceleration to gravitational acceleration on an object. 2. - The astronaut is seated in a reclined, contour couch seat facing the direction of acceleration such that they experience lateral g-force loads. An "eyeballs in" force is easier to cope with than an "eyeballs...

This site, youtube, reddit and minecraft.

Thanks, will fix it up

1. A black body is a hypothetical object that absorbs all incident EM radiation. 2. First, lets delve a bit in to what the classical wave-theory of light predicted. It predicted that the intensity of black body radiation (BBR) as wavelength got smaller would approach infinity (known as the UV...

A question worth that much involving the standard model of matter should involve other aspects too. Some things you could talk about depending on the question: - What is the standard model of matter - Components of it - Talk about accelerators and how they work -> link to discovery of particles...

Just added a few things and commented. Probably are things that you already knew, but just putting it out there :)