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4 years ago

How many atoms are in al2o3

Chemistry

1 answer:

wel4 years ago

8 0

<span>Ci sono 5</span><span><span> Spero che questo <span>ha aiutato</span></span> </span>

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A material has a volume of 63.0 cm3 and a mass of 28 grams. What is the density of the material in g/cm3 to the correct number

dimaraw [331]

Answer:

0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).

Explanation:

Knowing that:

where, d is the density of the material (g/cm³).

m is the mass of the material (m = 28 g).

V is the volume of the material (V = 63.0 cm³).

<em>∴ d = m/V </em>= (28 g)/(63.0 cm³) = <em>0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).</em>

7 0

3 years ago

4g of sugar is dissolved in 46 g of water calculate the concentration as percent by mass

Lina20 [59]

The concentration as % by mass is calculated as below

mass of solute/mass of solvent x100
mass of solute(sugar) = 4g
mass of solvent(water) =46 g

= 4g/ 46 g x100 = 8.7%

3 0

3 years ago

Read 2 more answers

6. How many moles of water would require 92.048 kJ of heat to raise its temperature from 34.0 °C to 100.0 °C? (3 marks)

scoray [572]

Taking into account the definition of calorimetry, 0.0185 moles of water are required.

<h3>Calorimetry</h3>

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

So, the equation that allows to calculate heat exchanges is:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

<h3>Mass of water required</h3>

In this case, you know:

Heat= 92.048 kJ
Mass of water = ?
Initial temperature of water= 34 ºC
Final temperature of water= 100 ºC
Specific heat of water = 4.186 $\frac{J}{gC}$

Replacing in the expression to calculate heat exchanges:

92.048 kJ = 4.186 $\frac{J}{gC}$ × m× (100 °C -34 °C)

92.048 kJ = 4.186 $\frac{J}{gC}$ × m× 66 °C

m= 92.048 kJ ÷ (4.186 $\frac{J}{gC}$ × 66 °C)

<u><em>m= 0.333 grams</em></u>

<h3>Moles of water required</h3>

Being the molar mass of water 18 $\frac{g}{mole}$ , that is, the amount of mass that a substance contains in one mole, the moles of water required can be calculated as:

$amount of moles=0.333 gramsx\frac{1 mole}{18 grams}$

<u><em>amount of moles= 0.0185 moles</em></u>

Finally, 0.0185 moles of water are required.

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8 0

3 years ago

How many grams of oxygen is needed to completelt react with of 9.30 of aluminum

Leona [35]

Hey there!

Given the reaction:

4 AI + 3O2 ------> 2 AI2O3

4 moles Al --------- 3 moles O2

9.30 moles Al --------- ?? moles O2

9.30 * 3 / 4 => 6.975 moles of O2

Molar mass O2 => 32.0 g

Therefore:

6.975 * 32.0 => 223.3 g of Oxygen

Hope that helps!

5 0

3 years ago

What is the electron configuration of a n3- anion?

asambeis [7]

Answer:

You can see in the above illustration of the periodic table that N is in Period 4, Group 5A, and p-block. Before reaching N, you will pass through the atomic orbitals 1s, 2s, and 2p. The electron configuration of N3- is N3-: 1s22s22p6 .

Explanation:

3 0

3 years ago