All categories

2 years ago

3

Chemistry

2 answers:

Murrr4er [49]2 years ago

7 0

Answer:

Look at the properties of Oxygen and Silicon - the two most abundant elements in the Earth's crust - by clicking on their symbols on the Periodic Table.

Explanation:

vfiekz [6]2 years ago

3 0

Answer:

D. silicon and oxygen

Explanation:

The most abundant elements on the earth's crust are silicon and oxygen. Silicon and oxygen forms a wide range of silicate minerals they are found in the crust.

There are many silicates which are derived from the basal units of silicon and oxygen combining together. Other atoms or elements then combines with the silicate framework.

Oxygen is about 46% abundant in the crust whereas silicon takes about 28% to be the second most abundant element on the crust.

Silicate minerals abounds in rocks and within the soil.

You might be interested in

Neutral atoms have the same number of protons as electrons. what would make the electrically charged magnesium ion, mg2+, neutra

Allushta [10]

Mg2+ is the positive ion of the neutral atom Mg. This means that the neutral atom Mg lost the two excess electrons in its outermost energy level and became a positive ion with the two excess positive charges. To become neutral again, the Mg2+ ion has to regain two electrons again to balance the negative charge with the excess two positive charges.

7 0

2 years ago

Given that H2(g) + F2(g) - > 2HF(g) delta H rxn = -546.6 kJ 2H2(g)+ O2(g) - > 2H2O(l) delta H rxn = 571.6 kJ

olasank [31]

Answer:

ΔHrxn = -521.6 kJ

Explanation:

To do this, let's write the equations by separate:

H₂ + F₂ -------> 2HF ΔH = -546.6 kJ

2H₂ + O₂ -------> 2H₂O ΔH = -571.6 kJ

For these reactions, we want to get the following reaction:

2F₂ + 2H₂O -------> 4HF + O₂ ΔHrxn = ?

To do this, all we have to do is take the first two reaction and put them in the way to obtain the third reaction. When we look the final reaction we can see that the water is on the reactants, when originally it was on the product, while Florine is doubled. So all we have to do is rewrite the first two reactions, duplicate the first reaction, and reverse the second reaction, and that way we will get the final reaction:

1) (H₂ + F₂ -------> 2HF ) x2 ΔH = -546.6 kJ x 2

2) (2H₂O --------> 2H₂ + O₂) ΔH = -571.6 kJ x -1

---------------------------------------------------------------------------

1) 2H₂ +2F₂ -------> 4HF ΔH = -1093.2 kJ

2) 2H₂O --------> 2H₂ + O₂ ΔH = +571.6 kJ

Now we sum 1) and 2). In this way, hydrogen cancels out and we do the same with the enthalpy:

1) 2H₂ +2F₂ -------> 4HF ΔH = -1093.2 kJ

2) 2H₂O --------> 2H₂ + O₂ ΔH = +571.6 kJ

---------------------------------------------------------------

2F₂ + 2H₂O -------> 4HF + O₂ ΔHrxn = -1093.2 + 571.6 = -521.6 kJ

So the enthalpy of this reaction is

<em>ΔHrxn = -521.6 kJ</em>

3 0

3 years ago

Considere un elemento "X" que posee como valencias 2, 4 y 6. En su nomenclatura tradicional, considerando la valencia cuatro, es

Ierofanga [76]

Answer:

"ite"

Explanation:

Se sabe que los elementos del grupo 16 de la tabla prioritaria muestran estados de oxidación o valencias de 2,4 y 6 respectivamente, dependiendo del compuesto formado.

Por ejemplo, el azufre forma los siguientes compuestos;

sulfato de sodio (el azufre tiene una valencia de 6)

Sulfito de sodio (el azufre tiene una valencia de 4)

Sulfuro de sodio (el azufre tiene una valencia de 2)

Por lo tanto, en compuestos en los que exhiben una valencia de 4, la terminación común es "ite"

8 0

2 years ago

Read 2 more answers

How many milliliters of 0. 0850 m naoh are required to titrate 25. 0 ml of 0. 0720 m hbr to the equivalence point?

charle [14.2K]

The volume of 0.0850 M NaOH is required to titrate 25.0 ml of 0.0720 M is 21.176 ml.

<h3>What are normality and molarity?</h3>

Normality is defined as the number of equivalents per litre of the solution

It is given by

Normality = number of equivalents / 1 L of solution

Molarity is defined as the number of moles of solute present in one litre of solution

Molarity = moles of solute / 1 litre of solution

Relationship between molarity and normality

Normality = Molarity × Acidity or Basicity of a salt

Here, the Acidity Of NaOH is 1 and the basicity of HBr is also 1.

Thus, Normality = Molarity

We know, N₁V₁ = N₂V₂

We can also write it as M₁V₁ = M₂V₂

V1 = $\frac{M_2V_2}{M_!}$

Substitute M₁ = 0.0850 M, M₂ = 0.0720 M, V₂= 25 ml

V1 = 21.176 ml

Hence, The volume of 0. 0850 m NaOH are required to titrate 25. 0 ml of 0. 0720 m is 21.176 ml.

Learn more about Normality and molarity:

brainly.com/question/9754178

#SPJ4

3 0

1 year ago

Read 2 more answers

Which of the following best describes isotopes?

LenKa [72]

Answer: An element with the same number of protons, but a different number of neutrons

Explanation:

The # of protons in an atom is what determines what atom it is (hydrogen has 1 proton, helium has 2 protons, etc ...). You cannot change the number of protons in an atom without changing what element the atom is.

The number of electrons in atoms varies greatly because electrons are constantly gained, lost, and shared during chemical reactions.

An isotope is a variation of the same element (so they must have the same # of protons) that have different masses (and therefore a different number of neutrons).

The answer is the fourth choice, "An element with the same number of protons, but a different number of neutrons"

8 0

2 years ago