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3 years ago

With reference to He-4 (or the diagram), explain the term isotopes.

Chemistry

1 answer:

boyakko [2]3 years ago

6 0

Answer:

Isotopes are basically atoms of an element that have an unequal number of neutrons and protons. Of course the proton number remains the same, but the neutron number either decreases or increases, which leads to an overall change in mass. However, no chemical properties of the atom/element are changed as the electrons are the same number and do not react. In regards to Helium 4, the original number of neutrons in Helium is 2, and protons 2 as well. We see an equal number of neutrons and protons, hence an unchanged mass, and the element is not an isotope.

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How many moles of sodium hydroxide would react with 1 Mole of sulphuric acid?

Paul [167]

Answer:

Two moles.

Explanation:

Sulphuric (sulfuric) acid $\rm H_2SO_4$ is a diprotic acid. When one mole of $\rm H_2SO_4$ molecules dissolve in water, two moles of $\rm H^{+}$ ions would be produced.

$\rm H_2SO_4 \to 2\, H^{+} + {SO_4}^{2-}$ .

On the other hand, sodium hydroxide $\rm NaOH$ is a monoprotic base. When one mole of $\rm NaOH$ formula units dissolve in water, only one mole of hydroxide ions $\rm OH^{-}$ would be produced.

$\rm NaOH \to Na^{+} + OH^{-}$ .

Note that $\rm H^{+}$ and $\rm OH^{-}$ react at a one-to-one ratio:

$\rm H^{+} + OH^{-} \to H_2O$ .

As a result, it would take $2\; \rm mol$ of $\rm OH^{-}$ to react with the $\rm 2\; mol$ of $\rm H^{+}$ that was released when $1\; \rm mol$ of $\rm H_2SO_4$ is dissolved in water. Since one mole of $\rm NaOH$ formula units could produce only one mole of $\rm OH^{-}$ , it would take $\rm 2\; mol$ of $\rm NaOH$ formula units to produce that $2\; \rm mol$ of $\rm OH^{-}$ for reacting with $1\; \rm mol$ of $\rm H_2SO_4$ .

3 0

3 years ago

The volume of the earth is approximately 1.08326x10 to the 12th power km to the 3rd power. How many liters is this

mafiozo [28]

Here, we are required to determine the volume of the earth which is 1.08326 × 10¹² km³ in liters.

The volume of the earth is approximately,

, 1.08326 × 10²⁴ liters

By conversion factors;

1dm³ = 1liter
However; 1km = 10000dm = 10⁴ dm
Therefore, 1km³ = (10⁴)³ dm³.

Consequently, 1km³ = 10¹²dm³ = 10¹²liters.

The conversion factor from 1km³ to liters is therefore, c.f = 10¹²liters/km³

Therefore, the volume of the earth which is approximately, 1.08326 × 10¹² km³ can be expressed in liters as;

1.08326 × 10¹² km³ × 10¹²liters/km³

The volume of the earth is approximately,

1.08326 × 10²⁴ liters.

Read more:

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7 0

2 years ago

Which of the following situations contains an example of a chemical reaction?

bogdanovich [222]

A bicycle rusting after it is left in the rain is an example of a chemical reaction because it involves oxidation (Option d).

<h3>What is a chemical reaction?</h3>

A chemical reaction can be defined as a phenomenon in which one or more substances called reactants react to form one or more different compounds, which are known as products.

A chemical reaction may include an enzyme that works to increase the seed of the reaction in normal conditions by lowering the activation energy of the reaction.

Therefore, we can conclude that a chemical reaction such as oxidation in a bicycle is a process where reactants combine or break down to form the products of such reaction.

Complete question:

Which of the following situations contains an example of a chemical reaction?

a. Ice forming after water is placed in a freezer

b. Watercolor paint drying on paper

c. a sugar cube dissolving in a glass of water

d. a bicycle rusting after it is left in the rain

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6 0

1 year ago

Which of the following groups of chemical elements would you expect to be most alike in their physical and chemical properties?

juin [17]

Many elements show very strong similarities to each other.For example, lithium (Li), sodium (Na), and potassium (K) are all soft, very reactive metals.

8 0

3 years ago

Question Ask “ Which Part Of The Ecological Pyramid Is Incorrect.”

shepuryov [24]

Primary producers i believe

4 0

3 years ago

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