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3 years ago

How many moles of calcium oxide are formed when 3 moles of calcium react with oxygen?

Chemistry

1 answer:

lions [1.4K]3 years ago

6 0

Answer:

3 moles of calcium oxide are formed

Explanation:

Based on the reaction of Calcium Ca, with oxygen, O₂, to produce calcium oxide, CaO is:

2Ca + O₂ → 2CaO

where 2 moles of calcium produce 2 moles of Calcium oxide.

That means, if 3 moles of Ca react in presence of oxygen:

3 moles of calcium oxide are formed

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The concentration of a biomolecule inside a rod‑shaped prokaryotic cell is 0.0035 M . Calculate the number of molecules inside t

timama [110]

Answer: This rod-shape prokaryotic cell has 3.740,734725‬ molecules

Explanation:

Step 1 : given data

Molarity of the prokaryotic cell = 0.0035 M

Length of the cell = 4.2 μm = 4.2 * 10^-6 m

diameter of the cell = 1.3 μm = 1.3 * 10^-6 m

Step 2: calculate volume

To calculate volume of a rod, weneef to know the radius.

V = r ² × l

The radius = half of the diameter : r = d/2 ⇒ (1.3 * 10^-6 m)/2 = 0.65 * 10^-6 m

V= (0.65 * 10^-6 m)² * 4.2 * 10^-6 m = 1.7745 * 10 ^-18 L

Step 3: Calculating number of moles

Number of moles = Concentration * Volume

moles = 0.0035 M * 1.7745 * 10 ^-18 L = 6.21075 * 10^-21 moles‬

Step 4: calculating number of molecules

1 mole contains 6.023 * 10 ^-23 molecules

6.21075 * 10^-21 moles contain : 6.21075 * 10^-21 * 6.023 * 10 ^-23 molecules = 3.740,734725‬ molecules

This rod-shape prokaryotic cell has 3.740,734725‬ molecules

4 0

3 years ago

Why is water typically used as the heat-absorbing liquid in calorimetry?

jenyasd209 [6]

It has a high specific heat. Meaning it takes a lot of heat for it to raise up 1 degree

8 0

3 years ago

How many moles of sucrose (C12H22O11) would be in 8.7 L of a 1.1 M solution of sucrose?

poizon [28]

Answer:

9.57 mol.

Explanation:

Molarity is defined as the no. of moles of a solute per 1.0 L of the solution.

M = (no. of moles of solute)/(V of the solution (L)).

∴ M = (no. of moles of sucrose)/(V of the solution (L)).

1.1 M = (no. of moles of sucrose)/(8.7 L).

∴ no. of moles of sucrose = (1.1 M)(8.7 L) = 9.57 mol.

5 0

4 years ago

Calculate the standard enthalpy of formation of carbon disulfide (CS2) from it's elements, given that C(graphite) + O2(g) → CO2(

ch4aika [34]

Answer:

Standard enthalpy of formation of Carbon disulfide CS2 = 87.3 KJ/mol

Explanation:

forming CS2 means that it should in the product side

C(graphite) + O2 → CO2 ΔH = -393.5

2S(rhombic) + 2O2 → 2SO2 ΔH = -296.4 x 2

CO2 + 2SO2 → CS2 + 3O2 ΔH = -1073.6 x -1

the second reaction is multiplied by 2 so that the SO2 and O2 can cancel out.

the third reaction is reversed (multiplied by -1) so that CS2 will be on the product side.

after adding the reaction and cancelling out similarities, the final reaction is: C(graphite) + 2S(rhombic) → CS2

Add ΔH to find the enthalpy of formation of CS2

ΔHf = (-393.5) + (-296.4 x 2) + (-1073.6 x -1) = 87.3 KJ/mol

be aware of signs

3 0

3 years ago

Given the equilibrium constants for the following two reactions in aqueous solution at 25 ∘C HNO2(aq)H2SO3(aq)⇌⇌H+(aq) + NO2−(aq

krok68 [10]

Answer : The value of $K_c$ for the final reaction is, 184.09

Explanation :

The equilibrium reactions in aqueous solution are :

(1) $HNO_2(aq)\rightleftharpoons H^+(aq)+NO_2^-(aq)$ $K_{c_1}=4.5\times 10^{-4}$

(2) $H_2SO_3(aq)\rightleftharpoons 2H^+(aq)+SO_3^{2-}(aq)$ $K_{c_2}=1.1\times 10^{-9}$

The final equilibrium reaction is :

$2HNO_2(aq)+SO_3^{2-}(aq)\rightleftharpoons H_2SO_3(aq)+2NO_2^-(aq)$ $K_{c}=?$

Now we have to calculate the value of $K_c$ for the final reaction.

Now equation 1 is multiply by 2 and reverse the equation 2, we get the value of final equilibrium reaction and the expression of final equilibrium constant is:

$K_c=\frac{(K_{c_1})^2}{K_{c_2}}$

Now put all the given values in this expression, we get :

$K_c=\frac{(4.5\times 10^{-4})^2}{1.1\times 10^{-9}}=184.09$

Therefore, the value of $K_c$ for the final reaction is, 184.09

4 0

3 years ago