What is part of every cell

What geological process(es) could form magnesium silicate perovskite at 500 C?

dimulka [17.4K]

Magnesium silicate is a compound of magnesium oxide and silicon. It is the magnesium salt of silicic acid containing an unspecified amount of water. The molecular formula can be expressed more clearly as MgSiO3.

7 0

2 years ago

Starting with the stock solution of 6.0 M, how many milliliters of 6.0 M sulfuric acid are needed to make 450 mL of 1.2 M soluti

Lina20 [59]

Answer: The volume of stock solution needed is 90 mL

Explanation:

To calculate the molarity of the diluted solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the stock sulfuric acid solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted sulfuric acid solution

We are given:

$M_1=6.0M\\V_1=?mL\\M_2=1.2M\\V_2=450mL$

Putting values in above equation, we get:

$6.0\times V_1=1.2\times 450\\\\V_1=\frac{1.2\times 450}{6.0}=90mL$

Hence, the volume of stock solution needed is 90 mL

6 0

3 years ago

Need some help, please. Explain why anions are always larger than the atoms from which they are derived, while cations are alway

ANTONII [103]

The question requires us to explain the differences in radii of neutral atoms, cations and anions.

To answer this question, we need to keep in mind that a neutral atom presents the same number of protons (positive particles) and electrons (negative particles). Another important information is that the protons are located in the nucleus of the atom, while the electrons are around the nucleus. Also, there is an electrostatic force between protons and electrons, which means that they the protons tend to attract the electrons to the nucleus.

While a neutral atom presents the same number of protons and electrons, a cation is an ion with positive charge, which means it has lost one or more electrons. In a cation, the balance between protons and electrons doesn't exist anymore: now, there is more positive than negative charge (more protons than electrons), and the overall attractive force that the protons have for the electrons is increased. As a result, the electrons stay closer to the nucleus and the radius of a cation is smaller than the neutral atom from which it was derived.

On the other side, anions present negative charge, which means they have received electrons. Similarly to cations, the balance between protons and electrons doesn't exist anymore, but in this case, there are more electrons than protons. In an anion, the overall attractive force that the protons have for the electrons is decreased. As a result, the electrons are "more free" to move and, as they are not so attracted to the nucleus, they tend to stay farther from the positive nucleus compared to the neutral atom - because of this, the radius of an anion is larger than the neutral atom from which it was derived.

3 0

1 year ago

1)

Delicious77 [7]

Answer:

C) How much energy was added to the substance to increase molecule motion?

Explanation:

The most relevant question to ask regarding this change must take into account the physical knowledge about matter.

When matter changes from liquid state to gaseous state, a physical change called evaporation, the particles (molecules or atoms) of the pure substance will separate from each other, take up more space and move faster.

Condensation is the opposite to evaporation, thus the option A) is not the most relevant question.

The charge of the particles does not change; so the option B) is not relevant at all.

The particles should gain energy from the surroundings to increase their motion (kinetic energy) when they pass from liquid state, where they move slower, to gas state, where they move faster. Hence, the option C), How much energy was added to the substance to increase molecule motion? , is totally relevant.

Since this is an increase in the kinetic energy of the molecules, the option D) is not relevant.

6 0

3 years ago

Sighting along the C2-C3 bond of 2-methylbutane, the least stable conformation (Newman projection) has a total energy strain of

natima [27]

Answer:

21 KJ/mol

Explanation:

For this question, we have to start with the linear structure of 2-methylbutane. With the linear structure, we can start to propose all the Newman projections keep it in mind that the point of view is between carbons 2 and 3 (see figure 1).

Additionally, we have several energy values for each interaction present in the Newman structures:

-) Methyl-methyl gauche: 3.8 KJ/mol

-) Methyl-H eclipse: 6.0 KJ/mol

-) Methyl-methyl eclipse: 11.0 KJ/mol

-) H-H eclipse: 4.0 KJ/mol

Now, we can calculate the energy for each molecule.

Molecule A

In this molecule, we have 2 Methyl-methyl gauche interactions only, so:

(3.8x2) = 7.6 KJ/mol

Molecule B

In this molecule, we have a Methyl-methyl eclipse interaction a Methyl-H eclipse interaction and an H-H eclipse interaction, so:

(11)+(6)+(4) = 21 KJ/mol

Molecule C

In this molecule, we have 1 Methyl-methyl gauche interaction only, so:

3.8 KJ/mol

Molecule D

In this molecule, we have three Methyl-H eclipse interaction, so:

(6*3) = 18 KJ/mol

Molecule E

In this molecule, we have 1 Methyl-methyl gauche interaction only, so:

3.8 KJ/mol

Molecule F

In this molecule, we have a Methyl-methyl eclipse interaction a Methyl-H eclipse interaction and an H-H eclipse interaction, so:

(11)+(6)+(4) = 21 KJ/mol

The structures with higher energies would be less stable. In this case, structures B and F with an energy value of 21 KJ/mol (see figure 2).

I hope it helps!

3 0

4 years ago