How many grams are in 3.0 moles of sodium chloride (NaCl)?

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

Answer: C

Explanation:

he never had evidence in the first place that was nearly enough.

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