Hey sir quick question. For question 6 after finding the moles of H2A why couldn’t we hv just times that by 10 to get the moles in 250cm^3 and then have done mass so 1.3g/moles? Why do we need to work out volume first and all? Kindly clarify. Thank you for the video.
Hi, after you find the moles of H2A in the 26.45cm3 titre there is a step you can do to make it easier that he doesn't address in the video. You want to find the moles in 250cm3 so you should do 250 / 26.45 and then whatever the answer for this is, multiply it by the moles of H2A you found (The calculation is 9.452 x 0.0014). This should give you 0.0132 and you can use this to find the Mr of H2A by doing 1.3 / 0.0132 =98.2. To answer your question, you can't times by 10 to get the moles of 250cm3 as the moles you worked out for H2A is for 26.45cm3 in the TITRE. (25cm3 is the volume of the sodium hydroxide). Hope this helps :)
The answer is A(atomic radius). As you go down group 2 (ca to ba) you get more electron shells which means the atomic radius(esentially the size) of the atoms get bigger as you have more and more shells. It can't be electronegativity because electron shielding means the force from the nucleus(protons) would be weaker on the outer electrons and electrons from other atoms so its less likely to be able to attract electrons from other atoms. can't be first ionisation energy because once again electron shielding(which increases the more electron shells you have) means the force of the nucleus on the outermost electrons is weaker as you go down the group. can't be melting point because as you go down the group the weaker nucleus force means metallic bonding gets weaker which reduces melting temps
This is really helpful, thanks
Thanks :-)
in question 9, where did 1/24 come from please
it is becuase V=mole x 24
and the unit of V is in dm cube
@@jack-cl5bp when is this formula used
@@ayo123when pressure and temperature are constant I think
@@missachin5054 just finished my exams but I preciate it
Hey sir quick question. For question 6 after finding the moles of H2A why couldn’t we hv just times that by 10 to get the moles in 250cm^3 and then have done mass so 1.3g/moles? Why do we need to work out volume first and all? Kindly clarify. Thank you for the video.
Hi, after you find the moles of H2A in the 26.45cm3 titre there is a step you can do to make it easier that he doesn't address in the video. You want to find the moles in 250cm3 so you should do 250 / 26.45 and then whatever the answer for this is, multiply it by the moles of H2A you found (The calculation is 9.452 x 0.0014). This should give you 0.0132 and you can use this to find the Mr of H2A by doing 1.3 / 0.0132 =98.2.
To answer your question, you can't times by 10 to get the moles of 250cm3 as the moles you worked out for H2A is for 26.45cm3 in the TITRE. (25cm3 is the volume of the sodium hydroxide). Hope this helps :)
skipped q18
The answer is A(atomic radius). As you go down group 2 (ca to ba) you get more electron shells which means the atomic radius(esentially the size) of the atoms get bigger as you have more and more shells. It can't be electronegativity because electron shielding means the force from the nucleus(protons) would be weaker on the outer electrons and electrons from other atoms so its less likely to be able to attract electrons from other atoms. can't be first ionisation energy because once again electron shielding(which increases the more electron shells you have) means the force of the nucleus on the outermost electrons is weaker as you go down the group. can't be melting point because as you go down the group the weaker nucleus force means metallic bonding gets weaker which reduces melting temps
my knowledge is somewhat rough but this is the main idea why the answer is atomic radius
@@ronicakmak3489 tysm