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Use this link http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/guys im finding chem aslevel practicals difficult
try this website out tooguys im finding chem aslevel practicals difficult
33) Valence shell electron pair repulsion theory should be used to answer this question. Which species are trigonal planar?
1 BH3
2 CH3+
3 PH3
the answer is B (1 and 2 only are correct)
can someone please explain how to use the Valence shell electron pair repulsion theory to answer this? i don't get it!
Solids W, X, Y and Z are compounds of two different Group II metals. Some of their applications are described below.
Compound W is used as a refractory lining material in kilns.
Compound X is used as a building material. It can also be heated in a kiln to form compound Y. When Y is hydrated, it forms compound Z which is used agriculturally to treat soils. Which statements about these compounds are correct?
1 More acid is neutralized by 1 g of W than by 1 g of X.
2 The metallic element in W reacts with water more quickly than the metallic element in Y.
3 Adding Z to a soil decreases the pH of the soil.
the answer is D (1 only is correct)
and here too please, i get that W is probably MgO, X is probably CaCO3, Y may be CaO and Z most likely Ca(OH)2. i know that 2 and 3 are wrong, but please explain why 1 is correct, thanks in advance!
Thank you so much! really helped me!VSEPR in simple terms states hat LP-LP repulsion> BP-LP repulsion > BP-BP repulsion.
And such repulsion will to an extent, determine molecular shapes.
All you have to do is follow the usual method of figuring out the number of lone pairs and bond pairs in a molecule to determine the shape.
1. 3 BP, 0 LP
2. 3 BP , 0 LP
3. 3 BP, 1 LP (trigonal pyramidal)
1g of MgO = 1/40 moles of MgO
1g of CaCO3 = 1/100 moles of CaCO3
Using HCl as example
MgO + 2HCl --> MgCl2 + H2O (HCl neutralised = 1/20 mol)
CaCO3 + 2HCl --> CaCl2 + CO2 + H2O (HCl neutralised = 1/50 mol)
Answer is D. Only student Y is correct. All the carbon atoms bonded in the ring have tetrahedral structure, and are sp3 hybridised. this is because every carbon is attached to four groups. So like when you draw optical isomers, in fact, every carbon with 4 substituents have a 3 dimensional tetrahedral structure. Therefore, they cannot be on the same plane. As for cis-trans, this is obvious, whenever a C=C double bond exists, a cis-trans isomerism is possible (not always but usually.)Asslamoalaikum
I need help with this question
The answer is B for that questions .. sorry maybe u might haven't noticed it ... :/Answer is D. Only student Y is correct. All the carbon atoms bonded in the ring have tetrahedral structure, and are sp3 hybridised. this is because every carbon is attached to four groups. So like when you draw optical isomers, in fact, every carbon with 4 substituents have a 3 dimensional tetrahedral structure. Therefore, they cannot be on the same plane. As for cis-trans, this is obvious, whenever a C=C double bond exists, a cis-trans isomerism is possible (not always but usually.)
Answer is D. Only student Y is correct. All the carbon atoms bonded in the ring have tetrahedral structure, and are sp3 hybridised. this is because every carbon is attached to four groups. So like when you draw optical isomers, in fact, every carbon with 4 substituents have a 3 dimensional tetrahedral structure. Therefore, they cannot be on the same plane. As for cis-trans, this is obvious, whenever a C=C double bond exists, a cis-trans isomerism is possible (not always but usually.)
The answer is B for that questions .. sorry maybe u might haven't noticed it ... :/
View attachment 51385 Why is it D?
True, and then the HCl reacts with MnO2 to form Cl2.View attachment 51398 is this lab preparation for chlorine correct? But haven't we studied Nacl with H2so4 makes HCL and not Cl2?:/
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