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3 years ago

Which allotrope of carbon is used in lubricants, sporting goods, and aircraft?

1 answer:

4 0

The allotrope of carbon that is used in lubricants, sporting goods, and aircraft is graphite. The answer is letter A. Graphite is a good conductor of heat and is very soft. The layers of lattice of each are bound to the adjacent layers by weak Van der Waals forces which allow the layers to slide over one another easily.

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112 g of aluminum carbide react with 174 g water to produce methane and aluminum hydroxide in the reaction shown below.

dolphi86 [110]

<u>Answer:</u> 4.999 moles of excess reactant will be left over.

<u>Explanation:</u>

Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.

Excess reagent is defined as the reagent which is left behind after the completion of the reaction.

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of aluminium carbide = 112 g

Molar mass of aluminium carbide = 143.96 g/mol

Putting values in equation 1:

$\text{Moles of aluminium carbide}=\frac{112g}{143.96g/mol}=0.778mol$

For the given chemical reaction:

$2Al_4C_3(s)+12H_2O(l)\rightarrow 3CH_4(g)+4Al(OH)_3(s)$

By the stoichiometry of the reaction:

2 moles of aluminium carbide reacts with 12 moles of water

So, 0.778 moles of aluminium carbide will react with = $\frac{12}{2}\times 0.778=4.668 mol$ of water

Given mass of water = 174 g

Molar mass of water = 18 g/mol

Putting values in equation 1:

$\text{Moles of water}=\frac{174g}{18g/mol}=9.667mol$

Moles of excess reactant (water) left = 9.667 - 4.668 = 4.999 moles

Hence, 4.999 moles of excess reactant will be left over.

8 0

2 years ago

Which natural resource is nonrenewable?

Veronika [31]

Oil or petroleum are nonrenewable resources, the others are renewable resources.

7 0

3 years ago

Read 2 more answers

Turn on Write equation. What you see is an equation that shows the original uranium atom on the left. The boxes on the right rep

My name is Ann [436]

Answer:

Uranium-238 undergoes alpha decay to form Thorium-234 as daughter product.

Explanation:

Alpha decay is indicative of loss of the equivalents of a helium particle emission. The reaction equation for this reaction is shown below:

$_{92} ^{238} U_{}$ → $_{90} ^{234} Th_{} + _{2} ^{4} He_{}$

I hope this explanation is clear and explanatory.

6 0

3 years ago

What is the enthalpy of formation (?H?f) of NaHCO3(s) from its constituent elements.

vova2212 [387]

Answer:

Enthalpy of formation = -947.68KJ/mol

Explanation:

Enthalpy of formation is the heat change when one mole of a substance is formed from its element in its standard states and in standard conditions of temperature and pressure. it may be positive or negative, if positive, it is an endothermic reaction where the heat content of the product is greater than that of the reactants, and if negative, it is exothermic reaction - where the heat content of the reactants is greater than the products. the enthalpy of formation is measured in KiloJoule/Moles (KJ/Mole).

From the value of the enthalpy of formation of NaHCO3, it shows that the reaction is exothermic, that is the formation of NaHCO3 from its constituents elements. As such, the heat content of the reactants is greater than the products.

The step by step explanation is shown in the attachment.

7 0

3 years ago

Read 2 more answers

A nuclear waste site. cesium-137 is a particularly dangerous by-product of nuclear reactors. it has a half-life of 30 years. it

hram777 [196]

The mass decay rate is of the form
$m(t) = m_{0} e^{-kt}$
where
m₀ = 3000 g,the initial mass
k = the decay constant
t = time, years.

Because the half-life is 30 years, therefore
$e^{-30k} = \frac{1}{2} \\\ -30k = ln(0.5) \\ k = \frac{ln(0.5)}{-30} =0.0231$

After 60 years, the mass remaining is
$m = 3000 e^{-0.0231*60} = 750 \, g$

Answer: 750 g

4 0

3 years ago