subject Chemistry, 22.03.2021 05:10 mrsroberts210 Scenario On Halloween, children prepared to go trick-or-treating with glow sticks. They prepared two glow sticks (“Glow Stick In” and “Glow Stick Out”) following the directions below. The light intensity was given a value of 10 for both Glow Stick In and Glow Stick Out. At 6:00, the children left Glow Stick In inside of the 25oC house and took Glow Stick Out outside in 10oC weather. At 8:00, they noticed the light intensity of Glow Stick Out at 10oC had decreased to 5. They immediately returned home and noticed the light intensity of Glow Stick In at 25oC had decreased to 7. At 9:00, both glow sticks were at 25oC. Glow Stick In had a light intensity of 6, and Glow Stick Out had a light intensity of 8. Using at least two scientific principles, write a scientific explanation that includes evidence that justifies or describes the change in light intensity of both glow sticks. Please use claim evidence reasoning

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.