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2 years ago

How many molecules of sodium oxide will be created if 275 grams of sodium reacts with excess oxygen?

Chemistry

1 answer:

musickatia [10]2 years ago

5 0

3.6 x 10²⁴molecules

Explanation:

Given parameters:

Mass of Na = 275g

Unknown:

Number of molecules of Na₂O =

Solution:

Since sodium is the limiting reactant, we first use it to find the number of mole of the Na₂O and transpose it into finding the number of molecules.

Given equation:

4Na + O₂ → 2Na₂O

Since the equation is balanced, let us find the number of moles of Na;

Number of moles = $\frac{mass}{molar mass}$ = $\frac{275}{23}$ = 11.96moles

From the equation of the reaction;

4 mole of Na produced 2 moles of Na₂O

11.96 moles of Na will produce $\frac{11.96 x 2}{4}$ = 6moles

1 mole of a substance = 6.02 x 10²³ molecules

6 moles of Na₂O = 6 x 6.02 x 10²³ molecules = 3.6 x 10²⁴molecules

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Number of moles brainly.com/question/1841136

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Student Exploration: Collision Theory Vocabulary: activated complex, catalyst, chemical reaction, concentration, enzyme, half-li

Alika [10]

Answer:

1. Hot water

2. A pile of wood shavings

Explanation:

Sugar can dissolve more quickly in hot water than in cold water because there is more energy in hot water molecules. Because they are moving faster, they have more energy to break the bonds that hold sugar together. There is also more energy available to break the hydrogen bonds that hold water together.

Wood shavings have a greater contact surface than the solid hunk of wood, which is why they have a higher calorific value and then they will catch fire more easily.

4 0

2 years ago

A 0.0035 M aqueous solution of a particular compound has pH = 2.46. The compound is (A) a weak base (B) a weak acid (C) a strong

slava [35]

Answer:

(a) A strong acid

Explanation:

We have given the pH of the solution is 2.46

pH=2.46

So the concentration of $H^+=10^{-pH}=10^{-2.46}=0.00346$

solution having H+ concentration more than $H^+=10^{-7}$ is acidic

Since in the given solution, H+ concentration is 0.00346 M which is more than 10^{-7}[/tex] so this is an acidic solution

Note-The concentration of $H^+$ decide the behavior of the solution that is, it is acidic or basic

7 0

2 years ago

Oxalic acid is a diprotic acid. calculate the percent of oxalic acid (h2c2o4) in a solid given that a 0.7984-g sample of that so

vlada-n [284]

This method of quantitative determination of percent purity is titrimetric reactions. These reactions most commonly involve neutralization reactions between an acid and a base. Then, we look at the neutralization reaction:

H₂C₂O₄ + 2 NaOH ⇒ Na₂C₂O₄ + 2 H₂O

So, we do the stoichiometric calculations. The important data we should know is the molar mass of oxalic acid which is equal to 90 g/mol.

(0.2283 mol/L NaOH * 0.3798 L * 1 mol H₂C₂O₄/ 2mol NaOH * 90 g/mol H₂C₂O₄) ÷ 0.7984 g *100%
= 488%

This is impossible. The purity can't be more than 100%. Looking at our calculations and the balance reaction, all steps were done correctly. So, I think there is some typographical error in the given. The mass of the sample should be 7.984 g. Then, the answer would be 48.87% purity.

5 0

2 years ago

Read 2 more answers

Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is the freezing point of a solution made by dissolving 0

ExtremeBDS [4]

Answer:

The freezing point will be $2.9^{0}C$

Explanation:

The depression in freezing point is a colligative property.

It is related to molality as:

$Depressioninfreezing point=K_{f}Xmolality$

Where

Kf= $20\frac{^{0}C}{m}$

the molality is calculated as:

$molality=\frac{moles_{solute}}{mass_{solvent}}$

$moles=\frac{mass}{molarmass}=\frac{0.694}{154}=0.0045mol$

$massofcyclohexane=25g=0.025Kg$

$molarity=\frac{0.0045}{0.025}=0.18m$

Depression in freezing point = $20X0.18=3.6^{0}C$

The new freezing point = $6.5^{0}C-3.6^{0}C=2.9^{0}C$

5 0

2 years ago

An unknown solid is entirely soluble in water. On addition of dilute HCl, a precipitate forms. After the precipitate is filtered

Karo-lina-s [1.5K]

Answer:

Pb(NO3)2

Cd(NO3)2

Na2SO4

Explanation:

In the first part, addition of HCl leads to the formation of PbCl2 which is poorly soluble in water. This is the first precipitate that is filtered off.

When the pH is adjusted to 1 and H2S is bubbled in, CdS is formed. This is the second precipitate that is filtered off.

After this precipitate has been filtered off and the pH is adjusted to 8, addition of H2S and (NH4)2HPO4 does not lead to the formation of any other precipitate.

The yellow flame colour indicates the presence of Na^+ which must come from the presence of Na2SO4.

5 0

1 year ago