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The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).

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Answer:

The motion towards or away from us based on the Doppler effect and corresponding red shift or blue shift.

Explanation:

The emission and absorption spectra demonstrates the lines where light has been absorbed by the atoms. The spikes can be observed due to atoms releasing photons at those wavelengths. Infrared and ultra violet waves can be observed during spectroscopy.

Answer:

Movement of water from the area of high concentration of solute to the area of low concentration of solute.

Explanation:

Diffusion can be defined as the movement of gas molecules from a region of high concentration to a region of lower concentration until an equilibrium is attained or reached. This mixing of gas molecules in the liquid or gaseous state is due to their kinetic energy of random motion i.e without requiring bulk motion.

This ultimately implies that, diffusion is a phenomenon through which gas molecules in either a gaseous or liquid state spread out in response to a concentration gradient, which is simply the difference in concentration of the gases across a space.

During diffusion, molecules move from areas of high concentration to areas of low concentration. Also, diffusion does not require energy to move molecules.

Hence, the process of diffusion can be described as movement of water from the area of high concentration of solute to the area of low concentration of solute.

A solute can be defined as a substance that is typically dissolved in a liquid solvent such as water, coffee, tea, etc., to produce a solution.

Which of the following statements best explains the trends in boiling points?

A. The atomic size increases down the group, and this decreases the strength of the intermolecular forces.

                                           A is incorrect

B. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.

                                            B is incorrect

C. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.

                                             C is correct

D. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

                                              D is incorrect

The boiling point increase down a group because the total number of electrons increases down the group, and this increases the strength of the intermolecular forces. Hence option C is correct.

Boiling point of a substance is the temperature at which the substance changes from its liquid state to vapour state. Boiling point of a molecule or compounds depends on the bond type, molecular weight, temperature and pressure.

For ionic compounds, boiling point will be higher since ionic bonds are stronger than covalent compounds. There is a periodic trend for the physical properties such as boiling point for elements in periodic table.

Down a group, the number of electrons increases and the atomic size also as well as the ionic character increases down a group . These two facts leads to higher intermolecular attraction, thus more temperature have to applied to weaken the bonds.

Higher temperature to be applied means the boiling point of the substance is higher. Therefore, boiling point down a group increases because of the higher intermolecular attraction as said in option C.

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Answer:

K°(g)* + 419 Kj/mole => K⁺(g) + e⁻

Explanation:

1st ionization step for potassium is the ionization of the 4s¹ electron. This requires 419 Kj/mole energy (endothermic). The reaction equation is ...

K°(g)* + 419 Kj/mole => K⁺(g) + e⁻

*note: Ionization of group IA metals requires they be in gas phase. That is, as shown by the Born-Haber Cycle** for formation of ionic compounds ...

K°(s) + 89.24 Kj/mole => K°(g); then ...

K°(g) + 419 Kj/mole => K⁺(g).

**Recommend review of Born-Haber cycle for formation of ionic compounds.

Answer:

56.7g

Explanation:

Density = mass/volume

According to this question, some lead (Pb) of certain weights was obtained on a fishing trip. The density of lead is given as 11.34g/mL. If the 50 weights are placed in a 250. mL box, the mass of the lead are as follows:

Density = mass ÷ volume

11.34g/mL = mass/250mL

mass = 250 × 11.34

mass = 2835g

Since the 50 weight of lead weighs 2835g, then the mass of each weight is calculated as follows:

= 2835/50

= 56.7g

The correct option is D. 2) Anti-bonding electrons or lone pairs. These lone pairs, and bonds helps to form the shape which keeps these electrons separate as possible.

Answer:

Explanation:

D = mass/volume.

for the units, I'll take it in g/L but I don't know which units you want.

4.44*10^5 mg =  0.444 grams.

0.444/7 = 0.0634 g/L

Answer:

If a body is accelerated by 10m/s^2, it means that the body's speed (or velocity to be precise) is increasing by 10m/s every second. That is, if the initial ...

Answer:

it's B

Explanation:

Climbing plants require an external support to grow vertically and enhance light acquisition. Vines that find a suitable support have greater performance and fitness than those that remain prostrate. Therefore, the location of a suitable support is a key process in the life history of climbing plants

Answer:

1. Organic Alcohol

2. Ester (specifically acetate ester)

3. Organic Alcohol

4. Carboxylic acid

5. Ketone

6. Ether

7. Amine

Explanation:

You can tell what type it is both from the nomenclature and looking at the functional group on the molecular structure. Hope this helps!

Answer:

Distance from the sea, ocean currents, direction of prevailing winds, shape of the land, latitude, temperature, air pressure and  distance from the equator.

Explanation:

Distance from the sea, ocean currents, direction of prevailing winds, shape of the land, latitude, temperature, air pressure and  distance from the equator are the factors that influence the climates of any region. These factors has a great impact on the climate of a region, those regions which are nearer to the equator experiences hot climate whereas those regions which are far from the equator having cold climatic conditions.

Answer:

-1

Explanation:

Answer:

It is right or wrong I cannot say if it is wrong forgive me.

Answer:

The energy in the system will likely be exchanged, but the matter will not be exchanged.

Explanation:

According to the first law of thermodynamics, also known as Law of Conservation of Energy, energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another. The law of conservation of mass also states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass cannot change.

Answer:

i is the correct answer.

Explanation:

the RAM of aluminum is indeed 27. And since the RAM of substances are measured in terms of the C-12 isotope then R indeed explains why the RAM Al is 27.

the universe formed through the big bang explosion, all of the elements on Earth have been cooked for billions of years in stars and then released in the universe through super- nova explosions.

Answer:

all of this

Explanation:

C.

This is basically the definition of percent composition which is how much mass a element contributes to a specific molecule.

Answer: B.

Explanation:

the relative amount of mass an atom contributes to a molecule

Answer:

C. Lithium

Explanation:

This image describes the trend in reactivity. Group 1 metals are always the most reactive so yeah :)

Answer:

1.43 M

Explanation:

We'll begin by calculating the number of mole of the solid. This can be obtained as follow:

Mass of solid = 8.60 g

Molar mass of solid = 21.50 g/mol

Mole of solid =?

Mole = mass / molar mass

Mole of solid = 8.60 / 21.50

Mole of solid = 0.4 mole

Next, we shall convert 280 mL to litre (L). This can be obtained as follow:

1000 mL = 1 L

Therefore,

280 mL = 280 mL × 1 L / 1000 mL

280 mL = 0.28 L

Thus, 280 mL is equivalent to 0.28 L.

Finally, we shall determine the molarity of the solution. This can be obtained as illustrated below:

Mole of solid = 0.4 mole

Volume = 0.28 L

Molarity =?

Molarity = mole / Volume

Molarity = 0.4 / 0.28

Molarity = 1.43 M

Thus, the molarity of the solution is 1.43 M.

Answer:

False  grams is not used

Explanation:

IDEAL GAS LAW

The ideal gas law states that PV = NkT, where P is the absolute pressure of a gas, V is the volume it occupies, N is the number of atoms and molecules in the gas, and T is its absolute temperature.  

It is necessary to use Kelvin for the temperature and it is conventional to use the SI unit of liters for the volume. However, pressure is commonly measured in one of three units:  kPa ,  atm , or  mmHg . Therefore,  R  can have three different values.

Answer:

Philippines, island country of Southeast Asia in the western Pacific Ocean. It is an archipelago consisting of more than 7,000 islands and islets lying about 500 miles (800 km) off the coast of Vietnam. Manila is the capital, but nearby Quezon City is the country's most-populous city.

Answer:

0.01

Explanation:

volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.

The Sun radiates sunlight (visible)  photons

Photons from the Sun strike Earth and become infrared photons.

Earth radiates infrared photons into the atmosphere

CO2 in the atmosphere absorbs infrared  photons.

CO2 in the atmosphere emits infrared photons back toward Earth.

Certain gases are known to contribute towards global warming. Such gases are called greenhouse gases. The infrared rays from the sun are absorbed by these gases as they are re-emitted from the earth and re-emitted.

The sun radiates photons to the earth which is re-radiated into outerspace from the earth's surface. CO2 and other greenhouse gases absorbs these gases and re-emit them to the earth thereby causing a gradually rise in the temperature of the earth called global warming.

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Answer:

Mass of ascorbic acid in the pill = 7.152 x 176.1/1000 = 1.26 g

Explanation:  

The mass of ascorbic acid in the pill would be,  

1.26 g  

Now,  

Moles of ascorbic acid = Moles of NaOH = 0.447 M x 16 ml = 7.152 mmol  

Mass of ascorbic acid in the pill = 7.152 x 176.1/1000 = 1.26 g

Burning a sugar cube is a chemical change. Fire activates a chemical reaction between sugar and oxygen. The oxygen in the air reacts with the sugar and the chemical bonds are broken. Burning sugar leads to reaction of sugar with oxygen in air and leads to formation of carbon dioxide and water. The change is irreversible and is thus a chemical change

Answer:

don't know

Explanation:

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here's the answer to your question

The relative mass of the magnesium oxide (MgO) is equal to 40 g. The percentage by mass of magnesium in MgO is 60 %.

The mass percentage of any element in a particular compound can be calculated from the number of parts by mass of the element in 100 parts by mass of a given compound.

Calculate the molar mass of the given compound by adding the atomic masses of the present elements. Then, the percentage of each element can be determined by dividing the total mass of the element by the molar mass of the compound multiplied by 100.

Given, the molecular formula of magnesium oxide is MgO. The atomic mass of Mg and O is 24 g and 16 g respectively.

The relative formula mass of the MgO = 40 g/mol

The mass percentage of the Mg = (24/40) × 100 = 60 %

Therefore, the mass percentage of the Mg in MgO is equal to 60 %.

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