In this case, given the described concept regarding the Avogadro's number, we can easily notice that 27.0 g of aluminium foil has 6.022x10²³ atoms as shown below based on the mass-mole-particles relationship:

$27.0gAl*\frac{1molAl}{27.0gAl} *\frac{6.022x10^{23}atoms \ Al}{1molAl} \\\\=6.022x10^{23}atoms \ Al$

Notice this is backed up by the fact that aluminium molar mass if 27.0 g/mol.

Best regards.

8 0

3 years ago

Which of the following is a measurement of an object's mass?

Brilliant_brown [7]

Answer:

10 Kilograms

Explanation:

"millimetres" is a unit of measurement and is used for measuring distances.

"newton" is a unit of weight and is used to represent the weight of an object

:kilograms" is the one used for measuring mass

5 0

3 years ago

When 20.0 g of KI are dissolved in 50.0 mL of distilled water in a calorimeter, the temperature drops from 24.0 °C to 19.0 °C. C

Reil [10]

<h2>Answer:</h2>

<h2>Explanations</h2>

The formula for calculating the amount of heat absorbed by the water is given as:

$\begin{gathered} q=mc\triangle t \\ q=50\times4.18\frac{J}{g^oC}\times(19-24) \\ q=50\times4.18\times(-5) \\ q=-1045Joules \\ q=-1.045kJ \end{gathered}$

Determine the moles of KI

$\begin{gathered} moles\text{ of KI}=\frac{mass\text{ of KI}}{molar\text{ mass of KI}} \\ moles\text{ of KI}=\frac{20g}{166g\text{/mol}} \\ moles\text{ of KI}=0.1205moles \end{gathered}$

Since heat is lost, hence the enthalpy change of the solution will be negative that is:

$\begin{gathered} \triangle H=-q \\ \triangle H=-(-1.045kJ) \\ \triangle H=1.045kJ \end{gathered}$

Determine the enthalpy of solution in kJ•mol-1

$\begin{gathered} \triangle H_{diss}=\frac{1.045kJ}{0.1205mole} \\ \triangle H_{diss}\approx8.67kJmol^{-1} \end{gathered}$

Hence the enthalpy of solution in kJ•mol-1 for KI is 8.67kJ/mol

4 0

1 year ago