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3 years ago

Why do we use molecular models to represent atoms?

1 answer:

6 0

The molecular model is physical model of the atomic system used to represent molecules and their processes. It is used to understand chemistry and generating and testing hypotheses and it is the most commonly used explicit representation of atoms.

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A hydrate of CoCl2with mass of 6.00g heated strongly. After cooling, the mass of anhydrate is 3.27g . How many grams of H2O were

OverLord2011 [107]

2.53 gm must be the ans. ...hope so

4 0

4 years ago

Who believed that a grain of sand could be divided indefinitely?

Ilya [14]

Answer:

Democritus

Explanation:

4 0

3 years ago

How many moles of air are there in a 3 L container at 1 atm pressure and 294 K?Use PV=nRT

Keith_Richards [23]

The ideal gas law states: $PV=nRT$

If we put in the data.

$1\cdot7=n\cdot8.31\cdot294 \\n=\boxed{2.865\cdot10^{-3}mol}=\boxed{2.865mmol}$

Hope this helps.

r3t40

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4 years ago

Which of the following statements about boiling points is true?

lutik1710 [3]

The boiling point of a substance is higher than its freezing point

5 0

3 years ago

Water ionizes by the equationH2O(l)⇌H+(aq)+OH−(aq)The extent of the reaction is small in pure water and dilute aqueous solutions

tia_tia [17]

Explanation:

$H_2O(l)\rightleftharpoons H^+(aq)+OH^-(aq)$

The value of $K_w$ :

$K_w=[H^+][OH^-]$

a. pOH = 3.51

The sum of pH and pOH is equal to 14.

pH + pOH = 14 (at 25°C)

pH = 14 - 3.51 = 10.49

The pH of the solution is defined as negative logarithm of hydrogen ion concentration in solution.

$pH=-\log[H^+]$

$10.49=-\log[H^+]$

$[H^+]=3.2\times 10^{-11}$

$3.2\times 10^{-11} M$ is the $H^+$ concentration for an aqueous solution with pOH = 3.51 at 25°C.

At a certain temperature, the pH of a neutral solution is 7.56.

Neutral solution means that concentration of hydrogen ion and hydroxide ions are equal.

$[H^+]=[OH^-]$

$7.56=-\log[H^+]$

$[H^+]=2.754\times 10^{-8} M$

The value of $K_w$ at at this temperature:

$K_w=[H^+][OH^-]$

$K_w=[H^+][H^+]$

$K_w=(2.754\times 10^{-8})^2=7.6\times 10^{-16}$

The value of $K_w$ at at this temperature is $7.6\times 10^{-16}$ .

5 0

4 years ago