Seasonal variation on earth is due to the

Iodine-131 decays with a half-life of 8.02

dlinn [17]

Radioactive material undergoes 1st order decay kinetics.

For 1st order decay, half life = 0.693/k

where k = rate constant

k = 0.693/half life = 0.693/8.02 = 0.0864 day-1

Now, for 1st order reaction,
k = $\frac{2.303}{t} X log \frac{initial.conc}{final.conc}$

Given: t = 6.01d, initial conc. = 5mg

∴0.0864 = $\frac{2.303}{6.01} X log \frac{5}{final.conc}$
∴ final conc. = 2.975 mg

3 0

3 years ago

What physical effect can change the boiling point of a substance?

AleksandrR [38]

The correct answer for the following questions that are presented above are these ones:
(1) b. Pressure. The physical effect can change the boiling point of a substance is the pressure.
(2) Evaporation only occurs at the surface of a liquid. TRUE.
(3) d. freezing. The change from liquid to solid, or the reverse of melting, is called freezing.

5 0

3 years ago

Read 2 more answers

Most elements are ____________. The _____________ elements on the left of the stair-step line on the ______________ of Elements

Vlada [557]

Answer:

metals, 88 , periodic table , luster , heat, electricity , thin, right, opposite , appearance , luster , malleable , ductile, opposite , shiny, moderately

Explanation:

metals, 88 , periodic table , luster , heat, electricity , thin, right, opposite , appearance , luster , malleable , ductile, opposite , shiny, moderately Is the answer.

(Hope this helps can I pls have brainlist (crown)☺️)

4 0

2 years ago

What are the differences between thermoplastics and thermosetting plastics? Give examples and draw a simple diagram to show what

Olenka [21]

on the basis of the reaction of heat in plastic , their are two types of plastics : 

<h2>Thermoplastic & Thermosetting plastics </h2>

Thermoplastics : Plastics which easily get deformed (become soft )on heating and also get bend easily are known as thermoplastics .

examples : polythene , polyvinyl chloride and polystyrene .

thermosetting plastics : plastics which once moulded into a shape do not become soft on heating and cannot be moulded again are called thermosetting plastics .

examples : bakelite , melamine and formica

4 0

3 years ago

a 4.18 g sample of a hydrocarbon is combusted in a bomb calorimeter that contains 974 g of water. the temperature of the water i

lys-0071 [83]

The heat of the reaction, in kJ, when 4.18 g of the hydrocarbon are combusted 775.70 kJ.

The heat energy is given as :

q = m c ΔT + Ccal ΔT

q = ( 974 g× 4.184 ×6.9) + 624 ×6.9

q = 32424.59 J

moles of hydrocarbon = 0.0418 mol

heat of combustion = 32424.59 J / 0.0418 mol

= 775707.89 J

= 775.70 kJ

Thus, A 4.18 g sample of a hydrocarbon is combusted in a bomb calorimeter that contains 974 g of water. the temperature of the water increases by 6.9 °C when the hydrocarbon is combusted. the calorimeter constant for the calorimeter was determined to be 624 J/°C. what is the heat of the reaction is 775.70 kJ.

To learn more about calorimeter here

brainly.com/question/28943378

#SPJ4

5 0

11 months ago