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4 years ago

5

A compound is a pure substance composed of two or more elements, combined by chemical means, in a definite ratio. Which containe

r resents a chemical compound?
A) Cl
B) H2O
C) N2
D) Na

1 answer:

strojnjashka [21]4 years ago

8 0

Answer:

H20

Explanation:

H20 (WATER) is a compound because its constituent atoms, oxygen and hydrogen are present in a definite ratio (1:2)

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a solution of prepared by dissolving 20.0 brams of mavni fluride (MgF2) in 80.0 of water (H2O). whag is the mole fraction of mag

Serjik [45]

Answer:

2000.1234 trebuie sa fie asa

3 0

3 years ago

If 12.4 mol of Ne gas occupies 122.8 L, how many mol of Ne would occupy 339.2 L under the same temperature and pressure? Record

8090 [49]

Answer:

3.43×10¹ mol

Explanation:

Given data:

Initial number of moles = 12.4 mol

Initial volume = 122.8 L

Final number of moles = ?

Final volume = 339.2 L

Solution:

The number of moles and volume are directly proportional to each other at same temperature and pressure.

V₁/n₁ = V₂/n₂

122.8 L/ 12.4 mol = 339.2 L / n₂

n₂ = 339.2 L× 12.4 mol / 122.8 L

n₂ = 4206.08 L.mol /122.8 L

n₂ = 34.3mol

In scientific notation:

3.43×10¹ mol

7 0

3 years ago

How many grams of H2O can be made from the combustion of 3.75 liters of C7H14 and an excess of O2 at STP?

Kitty [74]

Answer:

21.10g of H2O

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

2C7H14 + 21O2 —> 14CO2 + 14H2O

From the balanced equation above, 2L of C7H14 produced 14L of H2O.

Therefore, 3.75L of C7H14 will produce = (3.75 x 14)/2 = 26.25L of H2O.

Next, we shall determine the number of mole of H2O that will occupy 26.25L at stp. This is illustrated below:

1 mole of a gas occupy 22.4L at stp

Therefore, Xmol of H2O will occupy

26.25L i.e

Xmol of H2O = 26.25/22.4

Xmol of H2O = 1.172 mole

Therefore, 1.172 mole of H2O is produced from the reaction.

Next, we shall convert 1.172 mole of H2O to grams. This is illustrated below:

Number of mole H2O = 1.172 mole

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H2O =..?

Mass = mole x molar mass

Mass of H2O = 1.172 x 18

Mass of H2O = 21.10g

Therefore, 21.10g of H2O is produced from the reaction.

3 0

3 years ago

Acid & Base Calculations Calculate the hydronium ion concentration for each. Tell whether it is an acid or a base. 1. pH = 5

Anuta_ua [19.1K]

<u>Explanation:</u>

pH is the negative logarithm of hydronium ion concentration present in a solution.

If the solution has high hydrogen ion concentration, then the pH will be low and the solution will be acidic. The pH range of acidic solution is 0 to 6.9
If the solution has low hydrogen ion concentration, then the pH will be high and the solution will be basic. The pH range of basic solution is 7.1 to 14
The solution having pH equal to 7 is termed as neutral solution.

To calculate the pH of the solution, we use equation:

$pH=-\log[H_3O^+]$ ......(1)

To calculate the pOH of the solution, we use the equation:

pH + pOH = 14 ........(2)

<u>For 1:</u>

We are given:

pH = 5.54

Putting values in equation 1, we get:

$5.54=-\log[H_3O^+]$

$[H_3O^+]=2.88\times 10^{-6}M$

Now, putting values in equation 2, we get:

14 = 5.54 + pOH

pOH = 8.46

The solution is acidic in nature.

<u>For 2:</u>

We are given:

pOH = 9.7

Putting values in equation 2, we get:

14 = 9.7 + pH

pH = 4.3

Now, putting values in equation 1, we get:

$4.3=-\log[H_3O^+]$

$[H_3O^+]=5.012\times 10^{-5}M$

The solution is acidic in nature.

<u>For 3:</u>

We are given:

pH = 7.0

Putting values in equation 1, we get:

$7.0=-\log[H_3O^+]$

$[H_3O^+]=1.00\times 10^{-7}M$

Now, putting values in equation 2, we get:

14 = 7.0 + pOH

pOH = 7.0

The solution is neither acidic nor basic in nature.

<u>For 4:</u>

We are given:

pH = 12.9

Putting values in equation 1, we get:

$12.9=-\log[H_3O^+]$

$[H_3O^+]=1.26\times 10^{-13}M$

Now, putting values in equation 2, we get:

14 = 12.9 + pOH

pOH = 1.1

The solution is basic in nature.

<u>For 5:</u>

We are given:

pOH = 1.2

Putting values in equation 2, we get:

14 = 1.2 + pH

pH = 12.8

Now, putting values in equation 1, we get:

$12.8=-\log[H_3O^+]$

$[H_3O^+]=1.58\times 10^{-13}M$

The solution is basic in nature.

<u>For 6:</u>

We are given:

$[H_3O^+]=1\times 10^{-5}M$

Putting values in equation 1, we get:

$pH=-\log(1\times 10^{-5})$

$pH=5$

Now, putting values in equation 2, we get:

14 = 5 + pOH

pOH = 9

The solution is acidic in nature.

5 0

3 years ago

What makes scientists think that arctic areas were once warm?

kogti [31]

Answer:well the ice preserves the wooly mammoths

Explanation:its not just snow its bacteria witch means that once living to frozen thats how they know how it looks like and to see what animal its related to now day it related to the elephants

3 0

3 years ago