An atom X has a proton number of 19 and relative atomic mass of 39.

(i) How many electrons, protons and neutrons are there in an atom of X?

(ii) How many electrons will there be in the outer energy level (shell) of an atom of X?

(iii) What is the electronic configuration of X?

Explanation:

Hi, there!!!!

Let me simply clear you..

Yes,The tendency to gain electrons (in nonmetal) decreases when we go down group 17.

The reason for above answer is when we go downwards in periodic table then the atomic size increases with the addition of number of shells and force of attraction between the nucleus and valance shell decreases. The force of attraction between the nucleus and valance shell becomes weaker due to which the force of attracting the electrons gets decreased.

So, we can say that the tendency to gain electrons decreases as we go down in periodic table.

Hope it helps....

Answer:

cells arose from preexisting cells

Explanation:

Rudolph Virchow is a German biologist that built on the work of other scientists such as Theodor Schwan to contribute his own quota to the development of the cell theory as it is currently known.

After several studies, Virchow rejected the idea of spontaneous generation and accepted the initially rejected idea of cell division. He earlier believed that cell division only takes place is some special type of cells and not in all cells.

Even though Virchow was not the first to bring the idea of cells arising from preexisting cells, he was the one that popularized the idea and added it to the earlier belief that all living organisms are made up of cells.

Answer:

B

Explanation:

Answer:

The answer that completes the question are in BOLD:

At chemical equilibrium, the amount of PRODUCT AND REACTANT REMAIN CONSTANT because the RATES OF THE FORWARD AND REVERSE REACTIONS ARE EQUAL.

Explanation:

In a reversible chemical reaction, an equilibrium is said to be achieved when the rates of the forward reaction is equal to that of the reverse reaction. A reversible reaction is one in which products are formed from reactants simultaneously with the formation of reactants from products.

The combination of two or more substances called REACTANTS gives rise to another substance called PRODUCT, which can in turn give rise to Reactants again. With time, the rate at which the reactants give rise the products, which is called the FORWARD REACTION will be equal to the rate at which the products give rise to the reactants, which is called REVERSE REACTION. At this point, the chemical reaction is said to be in a STATE OF EQUILIBRIUM.

When the rate at which both reaction occurs becomes equal i.e. at an equilibrium state, the concentration of both the reactants and the products becomes constant i.e. no longer changes. Hence, the amount of the reactants forming the products is the same as the amount of products forming the reactants.

N.B: At chemical equilibrium, the amount of the reactants and products does not necessarily equals zero (0). It simply means that there is no net change in the concentration/amount of both reactants and products.

Answer:

hydrant flying with balloon, balloon has lithp letting air out, bee: really yum balloon

    =                           =                                 =                                   =

hydrogen              helium                     lithium                     beryllium

be bore on the balloon, balloon pops, hydrant drops and makes a car bomb

           =                                                                                                  =

    boron                                                                                              carbon

night row general gets hurt by car bomb nearby, that general gets off boat

        =                                

nitrogen

wearing oxygen mask, mask is full of fluride gel, then he got neon teeth

             =                                               =                                      =

         oxygen                                fluorine                                neon

(try making a story out of the elements, use your imagenation)

I will give u tips to learn whole periodic table

1. Break down the table into sections

2. Spread out the memorisation process

3. Learn the elements in a song

4. Make none sense words made from element symbols

5. Use colour to learn element groups

6. Use mnemonic device to help remember the order of elements

I am sure this will be helpful for uuu

Explanation:

Answer:

3.18 seconds

Explanation:

Given the following :

Volume of oxygen (V1) = 100cm^3

Time taken (t1) = 3 seconds

Volume of Sulphur (iv) oxide (v2) = 150cm^3

From Graham's Law of diffusion:

(r1/r2) = √(m1/m2)

Where r = rate of diffusion

m = molar mass

Note rate (r) = (volume / time)

[(V1/t1) ÷ (v2/t2)] = √(m1/m2)

(v1/t1) * (t2/v2) = √(m1/m2)

m1 = 02 = (16 * 2) = 32

m2 = SO2 = (32 + (16 * 2)) = 64

(100/3) * (t2/150) = √(32/64)

100t2 / 450 = √(32/64)

100t2 / 450 = √32 / 8

100t2 / 450 = √32 / 8

100t2 * 8 = 450 * √32

800t2 = 2545.5844

t2 = 2545.5844 / 800

t2 = 3.1819805

t2 = 3.18 seconds

It will take 3.18s for 150cm^3 of Sulphur (iv) oxide to diffuse through the same pot.

Answer:

1.43 mol

Explanation:

The percentage of carbon in urea is [CO(NH 2) 2] is 20%

Answer:

I believe it's A) an array of positive ions in a sea of electrons

Answer:

C. the same amount of energy as

Explanation:

Firstly, a chemical reaction can either absorb energy from its surroundings to occur or release energy into its surroundings as a product. The former and latter descriptions are called ENDOTHERMIC and EXOTHERMIC reactions respectively. An exothermic reaction is that which transfers energy, in form of heat, to its surroundings while an Endothermic reaction is that which absorbs energy (heat) from its surroundings.

However, a reversible reaction is that reaction in which the formation of products from reactants and reformation of the reactants from products occur simultaneously. Hence, the products of a reversible reaction can become the reactants and move in the opposite direction. For example:

Reversible reaction: A + B ⇆ C + D means;

A + B → C + D and;

C + D → A + B

In a case whereby the opposite reactions consist of an endothermic and exothermic reactions, the endothermic reaction absorbs the same amount of energy as the exothermic reaction releases.

According to the law of conservation of energy, no energy is lost during a reversible reaction. Hence, in order to achieve an equilibrium, the amount of energy absorbed by the endothermic reaction is the same as the amount of energy released in the opposite exothermic reaction.

Answer:

[tex]\boxed{It\ will\ shift\ to\ create\ less\ of\ substance\ A}[/tex]

Explanation:

If the concentration of any substance A in a dynamic equilibrium increases, The equilibrium will be  shifted to its opposite side so that Substance A can be created less and the substance opposite to A can be created more so that a "dynamic equilibrium" can again be established.

Answer:

The baseball is thrown twice as fast as the softball in the same direction.

Explanation:

Answer:

Reactions of sodium with water and dilute acid

Sodium reacts explosively with dilute HCl(aq) to produce NaCl(aq) and H₂(g)

2Na (s) + 2HCl(aq) → 2NaCl(aq) + H₂(g)

Sodium reacts violently with cold water to produce NaOH(aq) and H₂(g)

2Na (s) + H₂O(l)  → 2Na(OH)(aq) + H₂(g)

The produced hydrogen may become ignited and explode

Reactions of iron with water and dilute acid

Iron reacts very slowly with dilute acid to produce iron (II) chloride and hydrogen gas

Fe (s) + 2 HCl (aq) →  FeCl₂ (aq) + H₂ (g)

Iron does not react with cold water. Iron reacts only with steam

Explanation:

Cultural absolutism is the term for the belief that one's own culture is superior to other cultures.

Cultural absolutism is one of the perspectives which is common in anthropology, but it can  also be applied to non-scientific thoughts also. It assumes that there is a set of universal values which are objectively valid in every  situation.

Today, pure cultural absolutism is seen as a harmful effect of ethnocentrism focusing on  the belief that one's own culture is superior and the practice of holding other's cultures to the standard of our own. However, purely relativist anthropologists have also been critiqued for going too far, by  denying any common humanity and being too lenient towards morally questionable practices. Contemporary approaches try to find a balance between  the universal values, such as human dignity, and a more inclusive and relativistic side  of culture.

Learn more about cultural absolutism,here:

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Answer:

When you are going to measure small lengths or objects or when you are going to measure things with great accuracy.

Explanation:

There would be an increase in the concentration of carbonic acid - this is how an increase in carbon dioxide concentration influences the system.

In chemistry, a dynamic equilibrium lives once a reversible reaction occurs. Substances transition between the reactants and products at equal rates, indicating there is no net change. Reactants and products exist formed at such a rate that the concentration of neither changes. It is a precise example of a system in a steady state. After a time, a reversible reaction in a closed system can get what we call a dynamic equilibrium.

The correct answer is option D.

To learn more about dynamic equilibrium refer to:

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Answer:

waaaaaaaaaaqwwwwwwwwwwww

Answer:

An ionic bond is a chemical bonding involving the attraction between oppositely charged ions

Explanation:

On the periodic table, elements from group 1 and 7 are attracted to each other and when they bond, it's called ionic bonding. This is because of their valence electrons and ions.

Answer:

Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. It is one of the main types of bonding along with covalent bonding.

Answer:

The number of protons in an atom is different than the atom’s total mass.  

Explanation:

Mendeleev knew only that, with some anomalies, the properties of elements varied periodically with their atomic masses.

Moseley's X-ray experiments enabled him to remove these anomalies and to show that the properties of elements varied with their atomic numbers.  

Chadwick later discovered that the mass differences were caused by the presence of neutrons.

Answer:

Explanation:

[tex]Move \: the\:decimal \:point\:,\\3 \:times\:to\:the \:right = 24\\\\When \:the\:decimal\:point \: moves\\\:to\:the \:right\:it\:becomes\:a \:negative\:power\\\\0.024= 24 \times 10^-^3[/tex]

Answer: Water molecules from the dilute to the concentrated solution

Explanation:

During Osmosis if a solution is separerated by a semipermeable membrane, the solvent (typically water) from the less concentrated solution in terms of solute goes through the semipermeable membrane to the solution with the higher concentration so that the concentrations between the solutions can be balanced.

With the above solutions therefore, water molecules would move from the solution of 0.4M of sugar to the solution with a 0.7M of sugar through the semipermeable membrane.

During osmosis, water molecules move from the dilute to the concentrated solution.

OSMOSIS:

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Answer:

%m/v =70%

Explanation:

El %m/v es una unidad de concentración que se define como cien veces la división entre la masa de una sustancia (En gramos) y el volumen total en el que esta sustancia se encuentra (en mL).

En el problema, debemos hallar la masa de etanol (Alcohol) y el volumen total de la solución.

Masa alcohol:

Ya te la dan en el problema: 105g

Volumen solución:

Volumen agua: 15mL

Volumen etanol: 105g × (1mL / 0.798g) = 131mL

Volumen Jabón líquido: 4.5g × (1mL / 1.5g) = 3mL

Volumen: 15mL + 131mL + 3mL

149mL

Así, el %m/v de alcohol en la solución es:

%m/v = (105g / 149mL) × 100

Answer:

The answer is Neon

Answer:

neon

Explanation:

neon has a complete outer 2n shell

Answer:

1,103.47 milliliters

Explanation:

The total percentage of alcohol from solution A and solution B is 29. In a solution that is a mixture of solution A and B, the percentage of alcohol that would be contributed by solution A would be:--

                   11/29 x 100% = 37.93%

--while the percentage of alcohol that would be contributed by solution B would be:

               18/29 x 100 = 62.07%

Hence, if a mixture of A and B has 320 milliliters of alcohol, the amount of alcohol contributed by B would be:

                     320 x 62.07/100 =  198.624 milliliters

Now, remember that solution B is 18% alcohol. This means that the 18% alcohol content of solution B is 198.624 milliliters. Thus, the total volume of solution B would be:

                 198.624 x 100/18 = 1,103.47 milliliters.

Therefore, the total milliliters of solution B Amanda used would be 1,103.47.

Answer:

Heat of sublimation of Li(s) = 160.5 kJ/mol

Explanation:

Given that:

[tex]\mathtt{2Li(s) + \dfrac{1}{2} I_2(g) \to 2LiI(s)}[/tex]

ΔH = –292 kJ

The heat of formation for the above reaction =  –292 kJ × 2 =  -584 kJ/mol

[tex]\mathtt{Li^+_{(g)} + I^-_{(g)} \to LiI_{(s)}}[/tex]

The lattice energy of LiI(s) = -753 kJ/mol

[tex]\mathtt{Li(g)\to Li^+(g) + e^- }[/tex]

The ionization energy of LiI(s) = +520 kJ/mol

[tex]\mathtt{I_2_{(g)} \to 2I_{(g)} }[/tex]

The Bond Energy of I₂(g) = 151 kJ/mol

[tex]\mathtt{I_{(g)} + e^- \to I^-_{(g)}}[/tex]

The electron affinity of I(g) = -295 kJ/mol

Heat of sublimation: Sublimation is the process of changing of a solid matter into gas without passing through the liquid stage, Now, the molar heat of sublimation is the amount of energy that must be added to a mole of solid  to turn it directly into a gas without any interference through the liquid phase provided the pressure is  constant.

From  the above reactions: The heat of sublimation  of Li(s) can be calculated by the sum total of the following.

[tex]\mathtt{Li_{(s)} + \dfrac{1}{2} I_2_{(g)} \to LiI_{(s)} \ \ -292 kJ/mol} \\ \\\mathtt{I_{(g)} \to \dfrac{1}{2} I2(g) \ \ -75.5 kJ/mol} \\ \\ \mathtt{I^-(g) \to I(g) + e^- \ \ +295 kJ/mol} \\ \\ \mathtt{LiI(s) \to Li^+_{(g)} + I^-_{(g)} \ \ +753 kJ/mol} \\ \\ \mathtt{Li^+_{(g)} + e^- \to Li(s) \ \ -520 kJ/mol} \\ \\[/tex]

[tex]\mathtt{Li(s) \to Li(g)}[/tex] = (-292 +(-75.5)+295+753+(-520)) kJ/mol

[tex]\mathtt{Li(s) \to Li(g)}[/tex] =  160.5 kJ/mol

Heat of sublimation of Li(s) = 160.5 kJ/mol

it might be porous materials

Answer:

Air had the highest rate of absorption.  Air absorbs most of the suns heat and sun rays and air can move to different areas which are warm and colder.

Explanation:

Answer:

Hey there!

A scientist would try to determine the cause of the food poisoning, and see if the people who got poisoned had anything in common, for example: they ate at the same restaurant, they are all people of a certain age, etc.

Let me know if this helps :)

Answer:

Heat = 3138J

Explanation:

In the system, the sample of Copper is releasing heat that produce the increasing in the temperature of water.

Using the equation of calorimeter, we can find the heat released for the sample of copper (The same that is absorbed for the water):

Q = C×m×ΔT

Where Q is heat, C is specific heat (For water: 4.184J/molK), m is the mass of water (50g) and ΔT is change in temperature of water (40°C-25°C = 15°C)

Replacing:

Q = 4.184J/molK×50g×15°C

Q = 3138J is the heat released for the sample of Copper (The same absorbed for the water).

Answer:

heat=3138j

Explanation:

In the system, the sample of Copper is releasing heat that produce the increasing in the temperature of water.

Using the equation of calorimeter, we can find the heat released for the sample of copper (The same that is absorbed for the water):

Q = C×m×ΔT

Where Q is heat, C is specific heat (For water: 4.184J/molK), m is the mass of water (50g) and ΔT is change in temperature of water (40°C-25°C = 15°C)

Replacing:

Q = 4.184J/molK×50g×15°C

Q = 3138J is the heat released for the sample of Copper (The same absorbed for the water).

Hey there!:

Density = 30 mg/mL

Mass = 150 mg

Volume = ??

Therefore:

D = m / V

30 = 150 / V

V = 150 / 30

V = 5.0 mL

converts volume into liters :

5.0 mL / 1000 => 0.005 L or 5.0 x 10⁻³ L

Hope this helps!

Answer:

The correct option is

The gravitational force between them increases

Explanation:

According to Newton's law of universal gravitation states that the force of attraction between two bodies is directly proportional to the product of the masses of the bodies and inversely proportional to the square of the distance of their centers from each other.

The formula for universal gravitation is given as follows;

[tex]F_{1} = F_{2} =G \times \dfrac{m_{1} \times m_{2}}{r^{2}}[/tex]

Where;

F₁, and F₂ = The gravitational forces of attraction on each mass

G = The gravitational constant

m₁ = The mass of one body

m₂ = The mass of the body

r = The distance between the centers of the two bodies

Therefore, the gravitational force of attraction on each object is inversely proportional to the as the distance between the centers of the two bodies

When the distance between the centers of the two bodies decreases, the two objects are brought closer together, the gravitational force of attraction between them increases.

Answer:

Gravitational force between two objects of masses m1/m2

Explanation:

is defined by Gm1xm2/r^2, where G is a universal constant, and r is the distance between the masses. This shows you why B is wrong; it would increase. Also, A is not a good choice, as shown. In the case of B, it would increase by say, 2/1 to 4/1 by doubling ones mass. In C's case the bottom would decrease on the fraction alot (square) if they were moved closer, thus the force would be greater.

Explanation:

in other words the  answer is The gravitational force between them increases