What two things determine the average atomic mass of an element?

Which of the following is a chemical property? A. boiling point B. melting point C. density D. combustibility

nevsk [136]

Answer:

D

Explanation:

Because the other answers can not to be considered to be chemical properties.

Chemical means that the after the reaction the checal properties have changed in a way that it can no longer be called the same ad befor. In short, it can not be undone.

Burning a match is irriversable, meaning you can never go back to the previous situation because the chemical compounds have changed (dramatically).

Melted ice can be frozen again. Steam (evaporated water) can condensate to water which can be heated and can boil again. The chemical contents remain H2O.

6 0

3 years ago

How far is the earth from the sun?

GalinKa [24]

The answer should be 1 AU as it’s just about close to the number of miles from earth to sun.
Earth to sun in miles is -92.96
1 AU is- 92955807.3

5 0

3 years ago

A chemist carefully measures the amount of heat needed to raise the temperature of a 894.0g sample of a pure substance from to −

astraxan [27]

Answer:

C = 0.2349 J/ (g °C)

Explanation:

Mass, m = 894.0g

Initial Temperature = −5.8°C

Final Temperature = 17.5°C

Temperature change = 17.5°C - (−5.8°C) = 23.3

Heat, H = 4.90kJ = 4900 J

Specific heat capacit, C = ?

The relationship between these quantities is given by the equation;

H = mCΔT

C = H / mΔT

C = 4900 / (894)(23.3)

C = 0.2349 J/ (g °C)

4 0

3 years ago

How are energy and mass connected during the formation of an atom?

vodka [1.7K]

Answer:

Energy is absorbed, so the mass is increased. Energy is released, so the mass is increased

6 0

3 years ago

A sample of hexane (C6H14) has a mass of 0.580 g. The sample is burned in a bomb calorimeter that has a mass of 1.900 kg and a s

Talja [164]

Answer: The enthalpy of the reaction is -4134.3 kJ/mol

Explanation:

To calculate the heat absorbed by the calorimeter, we use the equation:

$q=mc\Delta T$

where,

q = heat absorbed

m = mass of calorimeter = 1.900 kg = 1900 g (Conversion factor: 1 kg = 1000 g)

c = heat capacity of calorimeter = 3.21 J/g.K

$\Delta T$ = change in temperature = 4.542 K

Putting values in above equation, we get:

$q=1900g\times 3.21J/g.K\times 4.542K=27701.66J=27.7kJ$

Heat released by the calorimeter will be equal to the heat absorbed by the reaction.

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of hexane = 0.580 g

Molar mass of hexane = 86.18 g/mol

Putting values in above equation, we get:

$\text{Moles of hexane}=\frac{0.580g}{86.18g/mol}=0.0067mol$

To calculate the enthalpy change of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

q = amount of heat released = -27.7 kJ

n = number of moles of hexane= 0.0067 moles

$\Delta H_{rxn}$ = enthalpy change of the reaction

Putting values in above equation, we get:

$\Delta H_{rxn}=\frac{-27.7kJ}{0.0067mol}=-4134.3kJ/mol$

Hence, the enthalpy of the reaction is -4134.3 kJ/mol

5 0

3 years ago