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2 years ago

How many moles of helium are 8.84×10^24 atoms of He?

Chemistry

1 answer:

viva [34]2 years ago

8 0

Answer:

14.77 mol.

Explanation:

It is known that every 1.0 mole of compound or element contains Avogadro's number (6.022 x 10²³) of molecules or atoms.

<u><em>Using cross multiplication:</em></u>

1.0 mole of He contains → 6.022 x 10²³ atoms.

??? mole of He contains → 8.84 x 10²⁴ atoms.

<em>∴ The no. of moles of He contains (8.84 x 10²⁴ atoms) </em>= (1.0 mol)(8.84 x 10²⁴ atoms)/(6.022 x 10²³ atoms) =<em> 14.77 mol.</em>

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What tool do you use to measure mass in chemistry?

Kryger [21]

Answer:

Balance Mass

Explanation:

It could be Balance 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

11 months ago

Why should the water in the calorimeter be stirred throughout the reaction?

Readme [11.4K]

I think this is done to allow even distribution of temperature in all the regions of the calorimeter. That is to make sure that there are no hot or cold spots and also ensure that the measured temperature is the actual average temperature when the readings are taken by a thermometer.

7 0

2 years ago

When a sample of a gas is heated in a sealed, rigid container from 200. K to 400. K, the pressure exerted by the gas is:

gavmur [86]

When a sample of a gas is heated in a sealed, rigid container from 200 degree Kelvin to 400 degree Kelvin, the pressure exerted by the gas is increased by a factor 2. Heating any gas actually increases the volume of the gas within a container. As the temperature of the gas rises, the molecules of the gas start moving faster and start striking the walls of the container in which it is kept with more force. The volume of the container tries to expand to accommodate the fast colliding molecules of the gas.

5 0

2 years ago

A 3.28 L solution is prepared by dissolving 535 g CaCl2 in water. The molar mass of CaCl2 is 110.98 g. What is the morality of t

andrey2020 [161]

Answer:

1.47 mol/L

Explanation:

Molarity is given as,

Molarity = Moles / Vol in L ------- (1)

Moles of CaCl₂,

Moles = Mass / M.Mass

Moles = 535 g / 110.98 g/mol

Moles = 4.82 mol

Now, putting values in eq. 1.

Molarity = 4.82 mol / 3.28 L

Molarity = 1.47 mol/L

5 0

2 years ago