which blue and violet gemstone is used as the birthstone for december?

Answer:

a difference in attitude

Explanation:

It's just not science. ... The big difference Popper identifies between science and pseudo-science is a difference in attitude. While a pseudo-science is set up to look for evidence that supports its claims, Popper says, a science is set up to challenge its claims and look for evidence that might prove it false.

Answer:

E\charged battery to provide electronic difference

Answer:  create more healthy products for the soil and animals

Explanation:

The answer is the last option, Zn + S ➡️ ZnS.

Answer:

45.98 I believe if its wrong im sorry

Answer:

there aren't any choices on the question so here's the closest i can give. A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure

Answer:

.

Considering the ideal gas law, the mass of hydrogen is 24.552 grams.

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P× V = n× R× T

In this case, you know:

Replacing in the ideal gas law:

1 atm× 1000 L = n× 0.082[tex]\frac{atmL}{molK}[/tex]× 298 K

Solving:

[tex]n=\frac{1 atmx1000 L}{0.082 \frac{atmL}{molK}x298 K}[/tex]

n= 40.92 mol

The mol of syngas mixture is 40.92 mol.

Syngas mixture contains 30.0% hydrogen. So, there is a mol fraction of [tex]x_{hydrogen} =[/tex]0.3 . Thus, the mols of hydrogen in syngas mixture is calculated as:

40.92 moles of syngas mixture× 0.3= 12.276 moles of hydrogen

Finally, being the molar mass of hydrogen H₂ 2 [tex]\frac{g}{mole}[/tex], then the mass is:

[tex]12.276 molesx\frac{2 grams}{1 mole}[/tex]= 24.552 grams

In summary, the mass of hydrogen is 24.552 grams.

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The free energy change of the reaction; Fe (s) + Au3+ (aq) -> Fe3+ (aq) + Au (s) is calculated to be -443.83KJ/mol.

For the reaction shown in question 7, we can divide it into half equations as follows;

Oxidation half equation;

6 Al (s) -------> 6Al^3+(aq) + 18e

Reduction half equation;

3Cr2O7^2-(aq) + 42H^+(aq)   + 18e -----> 6Cr^3+(aq) + 21H2O(l)

The balanced reaction equation is;

6Al(s) + 3Cr2O7^2-(aq) + 42H^+(aq)   -----> 6Al^3+(aq) + 6Cr^3+(aq) + 21H2O(l)

The E° of this reaction is obtained from;

E° anode = -0.04 V

E°cathode = +1.50 V

E° cell = +1.50 V - (-0.04 V) = 1.54 V

Given that;

ΔG° = -nFE°cell

n = 3, F = 96500, E°cell = 1.54 V

ΔG° = -(3 × 96500 × 1.54)

ΔG° = -443.83KJ/mol

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Answer:

i think this would be an example of a physical change because here the substance is changing directly from a solid to a gas without passing through the liquid state which means that the composition of the substance has not changed and remains the same. This is also called sublimation.

Answer:

Sulfur hexafluoride

Explanation:

It is heavier than air that we breathe so it has an opposite effect.

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Answer:

The bond between Phosphorus and Chlorine in PCl3 is covalent as chlorine needs one electron and phosphorus has metallic character and easily donate electron

Answer:

mercury i think

Explanation:

Answer:

Mercury is the densest liquid at standard conditions for temperature and pressure (STP). Also called quicksilver, mercury has been known for more than 3,500 years. It is an important metal in industry, but it is also toxic

Explanation:

Answer:

Only chemical equation uses arrow instead of = sign

Answer:

Only chemical equation uses an arrow instead of a = sign.

A chemical equation depicts a chemical reaction by utilising chemical formulae and symbols to depict the reactants, products, and chemical changes that take place. In a chemical equation, the arrow indicates the direction of the reaction and is commonly depicted as a single arrow pointing from the reactants to the products. In contrast, the equals sign (=) is commonly used in mathematical equations to indicate that two expressions have the same value.

While numbers are used to indicate the relative proportions of reactants and products and minus signs are used to indicate reactants or products in the form of ions, the arrow is the most distinguishing feature that distinguishes chemical equations from mathematical equations.

Answer:

Its development and progression are usually linked to a series of changes in the activity of cell cycle regulators. For example, inhibitors of the cell cycle keep cells from dividing when conditions aren't right, so too little activity of these inhibitors can promote cancer.

Superficially, the connection between the cell cycle and cancer is obvious: cell cycle machinery controls cell proliferation, and cancer is a disease of inappropriate cell proliferation. Fundamentally, all cancers permit the existence of too many cells.

Explanation:

hope it helps

may i ask?

How do you use this app?

Answer:

B, D, C

Explanation:

the solution may have more than one solute, a solution is a homogenous mixture of 2 or more substances and not all solutions are liquid

A solution is formed by the mixture of substances dissolved in water. There may have more than one solute. Not all solutions are liquid but there exists solid solutions too. Hence, options A, B, C are correct.

A solution is a combination of a solvent and a solid solute. The solute can be completely dissolved in the solvent and can have a partial solubility.

Water is a good solvent which dissolve majority of compounds. But there are other solvents too forming solution with suitable solutes. Solutions can be homogenous or heterogenous. Homogenous solutions are forming one phase and the solute particles are uniformly arranged.

Heterogeneous solutions are those where the solute particles are arranged in a non-uniformity and they form a different phase from the solvent.

There can be more than one solute in a solution provided that the solute can be of miscibility with each other.

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Answer:

A polar covalent bond is a covalent bond in which the atoms have an unequal attraction for electrons and so the sharing is unequal. In a polar covalent bond, sometimes simply called a polar bond, the distribution of electrons around the molecule is no longer symmetrical.

Explanation:

Answer:

O 7.94 x 10-8 M

Explanation:

Did the test

The hydronium ion concentration of a solution with a pOH of 6.90 is 7.94 × 10⁻⁸ M.

Relation between the pH and pOH will be represented by the below equation as:

pH + pOH = 14

Given that pOH = 6.90

So, pH = 14 - 6.90 = 7.1

Also we know that, pH = -log[H⁺]

[H⁺] = [tex]10^{-pH}[/tex]

[H⁺] = [tex]10^{-7.1}[/tex]M

[H⁺] = 7.94 × 10⁻⁸ M

Hence the concentration of hydronium ion is [tex]10^{-7.1}[/tex] M.

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The number of atoms of Hg in 4.5 mole sample has been given as [tex]\rm 2.7099\;\times\;10^2^4[/tex]. Thus, option A is correct.

The number of atoms in a mole of sample has been given by Avogadro number. Avogadro number has been a constant and has been given the value of [tex]\rm 6.023\;\times\;10^2^3[/tex].

The number of atoms in a mole of sample has been given as:

[tex]\rm 1\;mole=\;6.022\;\times\;10^2^3[/tex]

The given sample has been consisted of 4.5 moles of Hg. Thus, the number of atoms in the sample has been given by:

[tex]\rm 1\;mole\;Hg=\;6.022\;\times\;10^2^3\;atoms\\4.5\;mol\;Hg=4.5\;\times\;6.022\;\times\;10^2^3\;atoms\\4.5\;mol\;Hg=27.099\;\times\;10^2^3\;atoms[/tex]

The scientific notation has been the short hand used for writing the numbers. The short hand for atoms in 4.5 moles of Hg has been [tex]\rm 2.7099\;\times\;10^2^4[/tex].

Thus, the number of atoms of Hg in 4.5 mole sample has been given as [tex]\rm 2.7099\;\times\;10^2^4[/tex]. Thus, option A is correct.

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Silicon dioxide is a covalent network solid. Magnesium oxide is an ionic compound while carbon dioxide is a covalent molecule.

Carbon dioxide is a covalent compound. The compound contains polar C-O bonds but overall the compound is nonpolar as such the molecules are held together by only weak dispersion forces.

The compound magnesium oxide is an ionic solid. It is composed of magnesium ions and oxygen ions in a crystal lattice. Owing to the fact that the ions are very small, the lattice energy is large and the compound is almost insoluble in water.

Silicon dioxide is a covalent network solid which is composed of chains of silicon - oxygen bonds. The network solid forms a very rigid structure having a high melting point.

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Answer:

It's because it has 2 electrons on its outer ring

Explanation:

It has a -2 ion due to it having 2 more electrons than protons making it an overall negative. It's well known in chemistry that the first ring can only hold 2 electrons while the second and furthermore can hold up to 8. But what happens when you have 9? a new ring starts and it would only contain 1 electron.. In our case here it has 2 more electrons than protons and those 2 electrons are located on the outer ring

Answer:

+6

Explanation:

Answer:

Solid and does not conduct electricity

Explanation:

Answer:

it would be 53

Explanation:

because 4.00 L at 158kPa and 28c would be 53 grams of oxygine