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MAXImum [283]
3 years ago
9

How many moles are in 55.0 g calcium nitrate?

Chemistry
1 answer:
Alex17521 [72]3 years ago
5 0

Answer: 0.335 mols Ca(NO3)2

Explanation: To go from grams to mols you divide grams by the molar mass of the substance so, 55/164.088 = 0.335

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A useful single-displacement reaction involves thermite, which is a
Licemer1 [7]
The reaction of iron (III) oxide and aluminum is initiated by heat released from a small amount "starter mixture". This reaction is an oxidation-reduction reaction, a single replacement reaction, producing great quantities of heat (flame and sparks) and a stream of molten iron and aluminum oxide which pours out of a hole in the bottom of the pot into sand.

The balanced chemical equation for this reaction is:

2 Al(s) + Fe2O3(s) --> 2Fe(s) + Al2O3(s) + 850 kJ/mol

Curriculum Notes
This chemical reaction can be used to demonstrate an exothermic reaction, a single replacement or oxidation-reduction reaction, and the connection between ∆H calculated for this reaction using heats of formation and Hess' Law and calculating ∆H for this reaction using qrxn = mc∆T and the moles of limiting reactant. This reaction also illustrates the role of activation energy in a chemical reaction. The thermite mixture must be raised to a high temperature before it will react.

To determine how much thermal energy is released in this reaction, heats of formation values and Hess' Law can be used.

By definition, the deltaHfo of an element in its standard state is zero.

2 Al(s) + Fe2O3(s) --> 2Fe (s) + Al2O3 (s)

The deltaH for this reaction is the sum of the deltaHfo's of the products - the sum of the deltaHfo's of the reactants (multiplying each by their stoichiometric coefficient in the balanced reaction equation), i.e.:

deltaHorxn = (1 mol)(deltaHfoAl2O3) + (2 mol)(deltaHfoFe) - (1 mol)(deltaHfoFe2O3) - (2 mol)(deltaHfoAl)

deltaHorxn = (1 mol)(-1,669.8 kJ/mol) + (2 mol)(0) - (1 mol)(-822.2 kJ/mol) - (2mol)(0 kJ/mol)

deltaHorxn = -847.6 kJ

The melting point of iron is 1530°C (or 2790°F).
MARK ME BRAINLIEST

7 0
2 years ago
Which of the following is considered a renewable resource?
Mashutka [201]

Explanation:

I can give you some examples;

1) water

2) biomass

3)Soil

4) forest...

I hope this will help you

5 0
3 years ago
Read 2 more answers
A sample of PCl5(g) was placed in an otherwise empty flask at an initial pressure of 0.500 atm and a temperature above 500 K. Ov
tia_tia [17]

Answer:

Kp = 0.81666

Explanation:

Pressure of PCl₅ = 0.500 atm

Considering the ICE table for the equilibrium as:

                     PCl₅ (g)      ⇔          PCl₃ (g) +       Cl₂ (g)

t = o               0.500

t = eq                -x                             x                      x

--------------------------------------------- --------------------------

Moles at eq: 0.500-x                       x                      x

       

Given the pressure of PCl₅ at equilibrium = 0.150 atm

Thus, 0.500 - x = 0.150

x = 0.350 atm

The expression for the equilibrium constant is:

K_p=\frac {P_{PCl_3}P_{[Cl_2}}{P_{PCl_5}}  

So,

K_p=\frac{x^2}{0.500-x}  

x = 0.350 atm

Thus,

K_p=\frac{{0.350}^2}{0.500-0.350}  

<u>Thus, Kp = 0.81666</u>

7 0
3 years ago
Calculate the molecular weight when a gas at 25.0 ∘C and 752 mmHg has a density of 1.053 g/L . Express your answer using three s
stiks02 [169]

Answer:

26.0 g/mol is the molar mass of the gas

Explanation:

We have to combine density data with the Ideal Gases Law equation to solve this:

P . V = n . R .T

Let's convert the pressure mmHg to atm by a rule of three:

760 mmHg ____ 1 atm

752 mmHg ____ (752 . 1)/760 =  0.989 atm

In density we know that 1 L, occupies 1.053 grams of gas, but we don't know the moles.

Moles = Mass / molar mass.

We can replace density data as this in the equation:

0.989 atm . 1L = (1.053 g / x ) . 0.082 L.atm/mol.K . 298K

(0.989 atm . 1L) / (0.082 L.atm/mol.K . 298K) = 1.053 g / x

0.0405 mol = 1.053 g / x

x =  1.053 g / 0.0405  mol = 26 g/mol

7 0
3 years ago
Yall help, i missed like a week<br>some of them are wrong, I need all of 1 and 2​
Stolb23 [73]

Answer:

a. Azane

b. sulphur hexachloride

c.carbon tetrachloride

d. Carbon disulfide

e.Umbelliferone

f.Disilicon hexabromide

g. Dinitrogen trifluoride

h.

8 0
3 years ago
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