PLS HELP: Endocrine Organs Crossword

Answer:

Freeze wedging is caused by the repeated freeze-thaw. Frost wedging occurs as the result of 9% expansion of water when it is converted to ice. Cracks filled with water are forced further apart when it freezes.

Answer:

0.57 molecules

Explanation:

Answer:

ZnBr2

Explanation:

KNO3 + LiOH -------> no reaction

This is because KNO3 and LiOH completely ionize.in water and form neutral solutions.Since both are neutral no reaction occurs

NH4Cl + LiOH -----> NH3 (aq) + H2O (l) + LiCl(aq)

None of the above products are precipitates

Ca(C2H3O2)2 + 2LiOH -----> Ca(OH)2 (aq) + 2LiC2H3O2 (aq)

ZnBr2 + 2LiOH -----> Zn(OH)2 (s) + LiBr2 ( aq)

Zn(OH)2 thus formed is a white precipitate

However when excess LiOH is added Zn(OH)2 precipitate will dissolve to give a clear solution of Li2ZnO2 .

You can remember this by the fact that Na,K,Rb,Cs,Ca,Sr,Ba hydroxides are soluble in water and all other hydroxide are precipitated in water

Zn(OH)2 (s) + 2 LiOH ------> Li2ZnO2(aq) + 2 H2O ( l)

The only compound that will form a precipitate with LiOH would be ZnBr2

These are double displacement reactions in which precipitates are produced. Precipitates are insoluble solids formed from the combination of ions in aqueous solutions.

In this case, a reaction between LiOH and ZnBr2 would be as follows;

2LiOH + ZnBr2 ----------> 2LiBr + Zn(OH)2 (s)

Zn(OH)2 is an insoluble salt and will precipitate out in the solution.

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Answer:

Physical changes can be classified as reversible or irreversible. Melting is an example of a reversible physical change.

Explanation:

Answer:

1.Phenolphthalein

2.Method

a.Use the pipette and pipette filler to add 25 cm 3 of alkali to a clean conical flask.

b.Add a few drops of indicator and put the conical flask on a white tile.

c.Fill the burette with acid and note the starting volume.

d.Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.

Explanation:

Answer:

b

Explanation:

Answer:

C. sorry if I'm wrong ...................

This problem is giving information about the proton concentrations of three solutions at 25 °C. Despite they are not numerically given, we can propose three scenarios to see how to approach the question.

Let the following solutions to come up:

[H⁺] = 2.63x10⁻³ M

[H⁺] = 1.00x10⁻⁷ M

[H⁺] = 4.511x10⁻⁹ M

The first step, will be the calculation of the pH for each solution via:

pH = -log([H⁺])

So that they turn out to be:

pH = -log(2.63x10⁻³ M) = 2.580

pH = -log(1.00x10⁻⁷ M) = 7.000

pH = -log(4.511x10⁻⁹ M) = 8.3457

In such a way, since acidic solutions have a pH below 7, neutral have a pH equal to 7 and basic have it above 7, we infer the first one is acidic, second one is neutral and third one is basic.

Thus, you can reproduce this methodology with the proton concentrations you are given.

Learn more:

Answer: 3-nitropyridine

Explanation:

Answer:

Test for carbon dioxide gas.

The reaction between baking soda and citric acid will form sodium ions, citric acid ions, carbon dioxide gas, and water. So all you have to do is add the gas produced (by gas displacement method or something) and test whether the gas is carbon dioxide, with lime water or other methods like hydrogencarbonate indicator. Hope this helped!

Explanation:

Answer:

depends on amount, but the reaction's endothermic (meaning its cold, absorbs heat from surroundings)

I hope it helps.

Answer:

Explanation:

All the stars we see in the night sky are in our own Milky Way Galaxy. Our galaxy is called the Milky Way because it appears as a milky band of light in the sky when you see it in a really dark area.

Answer: it is

Explanation: A galaxy is a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction, plus there are 100 billion planet in it.

Answer:

the water in the mountains will take longer to boil, because of the higher atmospheric pressu

Answer:

c the answer is c that is the answer

Bond number

The characteristic of reactions that depends on valence electrons is the bond type.

In chemistry, a chemical bond could be;

Ionic

Covalent

The type of bond formed depends on the number of valence electrons present. When there are few valence electrons on an atom, it mostly forms ionic bonds.

When there are more electrons on an atoms, it mostly forms covalent bonds and the electrons between the atoms are shared.

Answer:

Explanation:

1) Organic compounds always contain only p-block elements (Groups III-VII), at least one of which must be carbon. 2) Organic compounds almost always contain one or more C-H bonds. ... Thus, all bonds are typically covalent in organic compounds. Methane (CH4) is the prototypical organic molecule.

Methane contains carbon, forming covalent bonds, and is found in living organisms, making it an organic compound.

Methane (CH₄) is considered an organic compound due to its molecular structure and occurrence in living organisms. Organic compounds are primarily composed of carbon atoms covalently bonded to hydrogen and often other elements like oxygen, nitrogen, sulfur, and more.

Methane consists of one carbon atom bonded to four hydrogen atoms through covalent bonds. Carbon's unique ability to form stable covalent bonds with other elements, including itself, leads to the vast diversity of organic molecules found in living organisms.

Methane is a crucial component of natural gas and is produced by various biological and geological processes. It is present in the digestive systems of animals, formed during decomposition, and plays a role in carbon and energy cycles.

Its prevalence in living systems and its molecular structure classify methane as an organic compound, reflecting the foundational principles of organic chemistry.

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The complete question is :

Methane is called an organic compound why​?

The energy of the photon with a frequency of 9.50×10¹³ Hz is 6.29×10¯²⁰ J

From the question given above, the following data were obtained:

Frequency (f) = 9.50×10¹³ Hz

Planck's constant (h) = 6.626×10¯³⁴ Js

The energy of the photon can be obtained as follow:

E = hf

E = 6.626×10¯³⁴ × 9.50×10¹³

Therefore, the energy of the photon is 6.29×10¯²⁰ J

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Answer:

see answer

Explanation:

DO the postulates of Daltons atomic theory explain the law of conservation of mass and the law of constant composition.

1. Everything is composed of atoms, which are the indivisible building blocks of matter and cannot be destroyed or divided any further.

2. All atoms of a single pure element are the same in size and mass

3. Atoms of different elements vary from each other in size and mass.

4. Compounds are produced through different simple whole-number combinations of atoms to produce molecules.  

5. Anywhere a compound exists, it will have the same atoms in the same ratio.

6. A chemical reaction between compounds is a re-arrangement of atoms

The law of conservation of mass is shown in 2, 4. and 5.

The law of constant co,position is shown in 2, 4, 5, and 6

In this exercise we want to calculate the amount of moles, so this is going to be:

[tex](4.6)(10^{-3}) \ mols \ CO_2[/tex]

Knowing that Henry's law is given by:

[tex]C = KHP[/tex]

Where constants are given by:

Before we can find the concentration of CO2 (and hence the moles of CO2), we first need to find its partial pressure.  We look up the vapor pressure of water at 25º and find it to be 0.03 atm.  Since the total pressure is equal to 0.1 atm, this mean the partial pressure of:

[tex]CO_2 = 0.1 \ atm - 0.03 \ atm = 0.07 \ atm[/tex]

Now using Henry's law, we find the concentration:

[tex]C = (0.033)*( 0.07) = (2.31)*(10^{-3})[/tex]

Converting to moles of CO2, we have:

[tex](2.31)*(10^{-3})*( 2) = (4.6)*(10^{-3})[/tex]

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