Answer:
A) Wood burning
system : Wood.
surroundings : atmosphere
Enthalpy : Exothermic
B) Water Freezing system
System : Refrigerator
surroundings : water in the refrigerator
enthalpy change : Endothermic
C) Sweat evaporating
System : Human being
surroundings : Air nearby
Enthalpy change : exothermic
D) Chemical Hand-warmer
system : Hand warmer pack
Surroundings : human palms
Enthalpy Change : Exothermic
Explanation:
A) Wood burning
system : Wood
surroundings : atmosphere
Enthalpy : Exothermic
This system give away energy to its surroundings hence its enthalpy change is exothermic
B) Water Freezing system
System : Refrigerator
surroundings : water in the refrigerator
enthalpy change : Endothermic
The system absorbs heat from what is put inside(surroundings ) of it hence this is na endothermic system
C) Sweat evaporating
System : Human being
surroundings : Air nearby
Enthalpy change : exothermic
This is an exothermic reaction ( enthalpy change ) because the system gives out heat to the surrounding
D) Chemical Hand-warmer
system : Hand warmer pack
Surroundings : human palms
Enthalpy Change : Exothermic
There is movement of heat from the system to the surrounding hence it is an exothermic reaction
Please help me l don’t understand please !!!!!!
Answer: C
Explanation:
he never had evidence in the first place that was nearly enough.
An organic compound which has the empirical formula CHO has an approximate
molar mass of 145 g/mol. What is its probable molecular formula?
Answer:
Molecular formula => C₅H₅O₅
Explanation:
From the question given above, the following data were obtained:
Empirical formula = CHO
molar mass of compound = 145 g/mol
Molecular formula =?
The molecular formula of the compound can be obtained as follow:
Molecular formula = Empirical formula × n
Molecular formula = [CHO]ₙ
[CHO]ₙ = 145
[12 + 1 + 16]n = 145
29n = 145
Divide both side by 29
n = 145 / 29
n = 5
Molecular formula = [CHO]ₙ
Molecular formula = [CHO]₅
Molecular formula => C₅H₅O₅