Which of the following element has more than one valence number. A.gold,b.iron,c.silver,d.aluminum

Answer:

The two main classes of molecules are polar molecules and nonpolar molecules. Some molecules are clearly polar or nonpolar, while others fall somewhere on the spectrum between two classes. Here's a look at what polar and nonpolar mean, how to predict whether a molecule will be one or the other, and examples of representative compounds.

Explanation:

so its c

An example of polar molecule is a molecule made of covalent bonds that has partial positive and partial negative charges in different areas of the atom.

Covalent bond is defined as a type of bond which is formed by the mutual sharing of electrons to form electron pairs between the two atoms.These electron pairs are called as bonding pairs or shared pair of electrons.

Due to the sharing of valence electrons , the atoms are able to achieve a stable electronic configuration . Covalent bonding involves many types of interactions like σ bonding,π bonding ,metal-to-metal bonding ,etc.

Sigma bonds are the strongest covalent bonds while the pi bonds are weaker covalent bonds .Covalent bonds are affected by electronegativities of the atoms present in the molecules.Compounds having covalent bonds have lower melting points as compared to those with ionic bonds.

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[tex]\begin{gathered}\boxed{\begin{array}{c}\\ {\pmb{\sf{Three \: equation \: of \: motion}}} \\ \\ \sf \star \: v \: = u \: + at \\ \\ \sf \star \: s \: = ut + \: \dfrac{1}{2} \: at^2 \\ \\ \sf \star \: v^2 - u^2 \: = 2as\end{array}}\end{gathered}[/tex]

[tex]\pink{\qquad \pmb{ \sf\longrightarrow v \: = u \: + at}}[/tex]

[tex] \qquad \pmb{\sf \longrightarrow v = 0 + 2.5 \times 2}[/tex]

[tex]\qquad \pmb{ \sf\longrightarrow v = 0 + 5}[/tex]

[tex] \qquad \pmb{\sf \longrightarrow v = 5 \: ms^{-1}}[/tex]

[tex]\qquad \longrightarrow {\pink{\underline{\underline{\pmb{\sf{ Final \: velocity= 5 \: ms^{-1} }}}}}}[/tex]

Henceforth –

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

Given what we know about the mechanisms surrounding the biological movement of substances, we can confirm that when two substances in a secondary active transport move in the same direction, it is called a symport.

A secondary active transport harnesses the electrochemical energy generated by its movement of one substance, to aid the movement of the other. These movements can be of two types, depending on the directions:

An antiport transport will move both substances in opposite directions, meaning one out of the cell and one into the cell. The transport described in the question is that of a symport, given that it moves both substances in the same direction.

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mix the food with digestive juices that have acids and enzymes, breaking it into much smaller, digestible pieces

Answer:

Pressure Cooking

Explanation:

Pressure cooking is a very old cooking method that’s experienced a recent resurgence thanks to a new generation of cookers that promise a speedy, set-it-and-forget-it path to dinner. These devices, whether electrical or stovetop, are all much safer than those of decades ago (which tended to explode), with mechanisms to prevent them from accumulating too much pressure. If you read the owner’s manual carefully, however, you’ll still find one important precaution to take when cooking under pressure: adding water. Water and pressure cooking go hand in hand. In fact, it’s water that helps generate the high-pressure environment that makes your food cook faster.

Most pressure cooker instructions state a minimum amount of water required for pressure cooking even a tiny amount of food. Inside the tightly sealed pressure cooker, the water is heated and eventually boils into steam. Since the steam cannot escape, it collects above the food. All those trapped water molecules increase the pressure inside the cooker.

Answer:

I think it's false but not sure

The atoms of platinum and silver are identical. This statement is false.

Platinum is a chemical element which is represented by the symbol Pt. Its atomic number is 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal.

The elements silver and platinum have the same properties in terms of ductility, malleability, and conductivity of heat and electricity.Platinum is more ductile than gold, silver or copper.

Both metals silver and platinum appear silver. They have gray undertones, unlike white gold which has a warmer, yellow undertone, instead platinum is much brighter and shinier and silver is a duller, gray appearance.

Thus, The atoms of platinum and silver are identical. This statement is false.

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Answer:

1.) Tin oxide + Carbon → Tin + Carbon monoxide.

2.) Lead oxide + Carbon → Lead + Carbon monoxide.

These equations show that the metals are being extracted by their oxides by heating with carbon. This is because the metals (Tin and Lead) are less reactive than carbon. Remember, extraction methods of metals are determined by their reactivity. Since the elements tin and lead are less reactive than carbon, the extraction process of heating with carbon is needed.  Remember that when a metal heats with carbon, the carbon displaces the metal from the compound and removes the oxygen from the oxide. Leaving you with the metal and carbon monoxide.

Answer:

Cellular Respiration:

C6H12O6 + 6O2 → 6CO2 + 6H20 + energy (Glucose + Oxygen yields Carbon Dioxide + Water + Energy) 

Photosynthesis is important to living organisms because it is the number one source of oxygen in the atmosphere. Without photosynthesis, the carbon cycle wouldn't occur/exist, oxygen-requiring life would not survive and plants would die. Without photosynthesis there would be little to no oxygen on the planet and Earth would be impossible to live on.

Answer:The mass of oxygen gas sample collected over water is 0.544 g.

The given parameters;

temperature of the oxygen gas, t = 25 °C

total pressure of the gas, P = 644 torr

volume of the gas, V = 500 mL

vapor pressure = 23.8 torr

molar mass of oxygen gas = 32 g/mol

The number of moles of the gas collected is calculated by using ideal gas equation as follows;

PV = nRT

where;

R is the ideal gas constant = 62.36 L.torr/mol.K

P is the pressure of the gas = 644 torr - 23.8 torr = 620.2 torr

T is the temperature of the gas = 25 + 273 = 298 K

V is the volume of the gas = 500 mL = 0.5 L

The number of moles of the  gas is calculated as follows;

The mass of oxygen gas collected is calculated as follows;

m = 0.017 (32 g/mol)

m = 0.544 g

Thus, the mass of oxygen gas sample collected over water is 0.544 g.

Explanation:

The partial pressure of oxygen is; 760.0 torr - 23.8  torr = 736.2 torr.

We know that in a mixture of gases, the pressure that is exerted by each gas is called the partial pressure of the mixture.

In this case, we have the total pressure of the mixture as 760.0 torr and the vapor pressure of water as 23.8 mm Hg or 23.8  torr) at that temperature. Hence, the partial pressure of oxygen is; 760.0 torr - 23.8  torr = 736.2 torr.

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Answer:

The forms of energy are:

These are the six forms hope you can write short notes on them.

Answer:

Hailstones are formed when raindrops are carried upward by thunderstorm updrafts into extremely cold areas of the atmosphere and freeze.

so i'm gonna guess and say that it does not matter because the rain drops freeze in the atmosphere in a cold place.

Explanation:

Hailstones are formed when raindrops are carried upward by thunderstorm updrafts into extremely cold areas of the atmosphere and freeze.

An atmosphere is defined as a blanket of gases that surrounds Earth which held near the surface of the planet by Earth’s gravitational force of attraction.

Argon, oxygen and nitrogen from the three main constituents of the atmosphere, it Helps to retain the sun’s heat and prevents it from escaping back into space, Protects life from harmful radiation, Plays a major role in Earth’s water cycle.

The atmosphere has five distinct layers which are determined by the changes in temperature and it happen with increasing altitude. Layers of Earth’s atmosphere are divided into five different layers as  Exosphere

Thermosphere, Mesosphere, Stratosphere, Troposphere

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Answer: Atom

..............................................

Answer:

the charge or oxidation number on the cation and anion.

Explanation:

The factor that governs the formula of an ionic compound such as Ca3N2 is the charge or oxidation number on the cation and anion.

In the example, Ca has a +2 charge, N has a -3 charge

So we need 3 x ( +2) to balance 2 x (-3) and have an electrically neutral compound, so

+6 -6 =0

The factor that governs the formula of an ionic compound such as Ca₃N₂ is charge.

Those compounds in which ionic bond is present between the cation and anion is known as ionic compound.

The most important factor that is essential for the formation of ionic compounds are charge i.e. positive charge and negative charge. In the given compound Ca₃N₂, Calcium (Ca) is present in the +2 oxidation state and Nitrogen is present in the -3 oxidation state. So due to attraction between these charges they make a ionic compound.

Hence charge is important factor.

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Answer:

because they are saturated

Answer:

Mass and gravitational for e is not relart

Answer:

Al2 (SO4)3

2×27 + 3×(32+ 4×16)

54 + 3×(32+ 64)

54+ 3×(96)

54+ 288

=342g

BRAINLIST PLS

Answer:

sdfs

Explanation:

dfssdf

When 1-bromo-2-methylpropane is reacted with methoxide the same product 1-methylprop-2-ene is obtained. This reaction is attached in image below:

The SN2 reaction is a nucleophilic substitution reaction that breaks one bond while forming another. The rate-determining step of the reaction involves two reacting species. SN2 is an abbreviation for Substitution Nucleophilic Bimolecular.

The reaction is bimolecular because two molecules are present in the transition state, as indicated by the number 2 in the SN2 symbol. As a result, the rate of the reaction is affected by the concentrations of both the nucleophile and the substrate.

The SN2 reaction is a nucleophilic substitution with two components in the rate determining step. -SN2 reactions are bimolecular, with bond-forming and bond-breaking steps occurring simultaneously. There is no intermediate in -SN2 reactions.

Thus, product 1-methylprop-2-ene is obtained.

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Answer:

An ion is a charged atom or molecule. It is charged because the number of electrons do not equal the number of protons in the atom or molecule. An atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

Explanation:

after learning more about the position and would

Answer:

5.57 x 10^24 atoms

Explanation:

first, you are seeking the number of ATOMS of Boron.

Boron has an Atomic mass of 10.8 g/mol (see #5 on the periodic table)

100 gm of Boron would have 100 g /10.8 g/mol =9.26 moles

each mole has Avogadros number of atoms 6.02 x 10^23

9.26 moles has 9.26 x 6.02 x 10^23 atoms =5.57 x 10^24 atoms

Answer:

c. pairs of electrons are shared between two nonmetal atoms

Explanation:

Bonding between elements solely depends on their electronegativity. When there is large difference in electronegativity, those atoms form ionic bonds. Covalent bonds form when the difference is minimal, or none at all. When the difference between electronegativities is 0 or very close to 0, then they form pure covalent bonds, or nonpolar bonds. An example of this are diatomic molecules. Diatomic molecules are two of the same atom that form nonpolar covalent bonds because their electronegativy difference is 0, as they have the same electronegativity. When the electronnegativties have bit of difference, they form polar covalent bonds.

Answer:

and id say maybe

Explanation:

Light waves travel much faster than sound waves.

Answer:

B

Explanation:

so A is nosense C and D the question is saying the stament for a being repersentation of solid not whether eletric or not

Answer:-

a. Non metals

b. Metals

c. Metals

d. Nonmetal

e. Metalloid

f. Metalloid

g. Metal

h. Nonmetal

i. Metal

j. Metal

k. Nonmetal

l. Nonmetal

Hope this helps you!

Answer:

An exothermic reaction is defined as a reaction that releases heat and has a net negative standard enthalpy change. Examples include any combustion process, rusting of iron, and freezing of water.

Explanation:

An exothermic reaction is defined as a reaction that releases heat and has a net negative standard enthalpy change. Examples include any combustion process, rusting of iron, and freezing of water.

The combustion is an example of an exothermic reaction.

An exothermic reaction is a reaction that releases energy, this energy is usually in the form of heat. An endothermic reaction is a reaction that absorbs energy to take place.

Analyzing the given reactions we have that:

So, the combustion is an example of an exothermic reaction.

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Answer: the answer is plasma membrane

Explanation:

Plasma membrane is made up of lipoproteins. There are two layers of lipids and the protein molecules are embedded in it. It is present in both plant cell and animal cell. The membrane is selectively permeable i.e., it allows only certain substances to pass.

The parts of the cell is made up of lipoprotein is Plasma Membrane. So, the correct option is (B).

The plasma membrane is made up of lipoproteins. There are two layers of lipids and protein molecules are embedded in it. It is present in both plant cell and animal cell. The membrane is selectively permeable i.e. it allows only certain substances to pass through.

The plasma membrane is also called the cell membrane which is a biological membrane that separates and protects the interior of all cells from the external environment. The plasma membrane controls the transport of materials entering and exiting the cell.

It provides a definite environment inside the cell. It also has many different functions such as transporting nutrients into the cell and removing toxins from the cell. The second is that the membrane of the cell, which would be the plasma membrane, would contain proteins that interact with other cells.

Thus, the parts of the cell is made up of lipoprotein is Plasma Membrane. So, the correct option is (B).

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Answer:an amino acid

Explanation:

For me this was the correct answer on a castle learning

Answer:

p=F/A.Explanation:

Answer:

example of a medium, it requires a transverse