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4 years ago

Argon-40 undergoes positron emission

Chemistry

1 answer:

san4es73 [151]4 years ago

8 0

Answer:

On the Earth, 40Ar makes up 99.6% of natural argon. ... The naturally occurring 40K, with a half-life of 1.248×109 years, decays to stable 40Ar by electron capture (10.72%) and by positron emission (0.001%), and also transforms to stable 40Ca via beta decay (89.28%).

Explanation:

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A copper atom has a mass of 1 06 times 10^-22 g and a penny has a mass of 2.5 g. Use this information to answer the questions be

amm1812

Answer:

Mass of 1 mole of copper is 63.83 g.

0.03916 moles of copper atoms have a mass equal to the 2.5 grams of copper penny.

Explanation:

Mass of 1 copper atom,m = $1.06\times 10^{-22} g$

$1 mole = 6.022\times 10^{23} atoms$

Mass of 1 mole of copper :

= $6.022\times 10^{23} atoms\times 1.06\times 10^{-22} g=63.83 g$

Mass of 1 mole of copper = 63.83 g

Mass of copper penny = 2.5 g

Atomic mass of copper = 63.83 g/mol

Moles of copper in 2.5 g of copper penny:

$\frac{2.5 g}{63.83 g/mol}=0.03916 mol$

0.03916 moles of copper atoms have a mass equal to the 2.5 grams of copper penny.

8 0

3 years ago

Consider the Fischer ester synthesis of methyl benzoate from benzoic acid and methanol in the presence of sulfuric acid as a cat

zlopas [31]

Answer:

48.8%

Explanation:

The reaction has a 1:1 mole ratio so;

Number of moles of benzoic acid reacted = mass/molar mass = 3.8 g/122.12 g/mol = 0.03 moles

So;

0.03 moles of methyl benzoate is formed in the reaction

Mass of methyl benzoate formed = 0.03 moles * 136.15 g/mol = 4.1 g

percent yield = actual yield/theoretical yield * 100/1

percent yield = 2.0 g/4.1 g * 100 = 48.8%

4 0

3 years ago

Sodium tert-butoxide (NaOC(CH3)3) is classified as bulky and acts as Bronsted Lowry base in the reaction. It is reacted with 2-c

IceJOKER [234]

Answer:but-1-ene

Explanation:This is an E2 elimination reaction .

Kindly refer the attachment for complete reaction and products.

Sodium tert-butoxide is a bulky base and hence cannot approach the substrate 2-chlorobutane from the more substituted end and hence major product formed here would not be following zaitsev rule of elimination reaction.

Sodium tert-butoxide would approach from the less hindered side that is through the primary centre and hence would lead to the formation of 1-butene .The major product formed in this reaction would be 1-butene .

As the mechanism of the reaction is E-2 so it will be a concerted mechanism and as sodium tert-butoxide will start abstracting the primary hydrogen through the less hindered side simultaneously chlorine will start leaving. As the steric repulsion in this case is less hence the transition state is relatively stabilised and leads to the formation of a kinetic product 1-butene.

Kinetic product are formed when reactions are dependent upon rate and not on thermodynamical stability.

2-butene is more thermodynamically6 stable as compared to 1-butene

The major product formed does not follow the zaitsev rule of forming a more substituted alkene as sodium tert-butoxide cannot approach to abstract the secondary proton due to steric hindrance.