true or false
In order to calculate the relative formula mass for any compound, we sum up the products of atoms of elements multiplied by their relative atomic mass.

Answer

Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.

Statement that can be considered true as regards periodic table is : A: Elements in the same column share similar properties.

Therefore, option A is correct.

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Answer:

Arsenic

Explanation:

The atom that has the lowest first ionization energy is Arsenic.

The first ionization energy is the energy needed to remove the most loosely bound electron of an atom in the gas phase in the ground state.

Ionization energy generally deals with the measure of the readiness of an atom to lose an electron.

Answer:

point 2 and 4

Explanation:

because at those point temperature is constant

Answer: 2) Electron X absorbs energy when it changes to a higher energy level.

Explanation:

The electrons in an atom exist in various energy levels. When an electron moves from a lower energy level to a higher energy level, energy is absorbed by the atom. When an electron moves from a higher to a lower energy level, energy is released (often as light).

Answer:

1/16

Explanation:

We have the half life of ²⁰O = 15 seconds

This half life means that the reactant 8s going to be half at this time

Now we have 60 seconds = 1 minute

Then in 60 seconds we are going to have 4 half life.

Then ²⁰O will be 1/2⁴

1/2⁴ = 1/16

This is the answer to this question.

Thank you!

1/16 fraction of a sample of pure ²⁰O remains after 1.0 minute

Given:

The half life of ²⁰O = 15 seconds

This half life means that the reactant 8s going to be half at this time

Now, we have 60 seconds = 1 minute

Then in 60 seconds we are going to have 4 half life.

Then ²⁰O will be 1/2⁴

1/2⁴ = 1/16

Thus, the fraction of a sample of pure ²⁰O remains after 1.0 minute is 1/16.

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Answer:

Exfoliation involves the removal of the oldest dead skin cells on the skin's outermost surface. Exfoliation is involved in all facials, during microdermabrasion or chemical peels. Exfoliation can be achieved by mechanical or chemical means.

Explanation:

I did copy off internet!

:P

Answer:

D. -1882J

Explanation:

We can solve the energy released in a chemical reaction in an aqueous medium using the equation:

Q = -m*C*ΔT

Where Q is energy (In J),

m is mass of water (45.00g)

C is specific heat of water (4.184J/g°C)

And ΔT is change in temperature (25.00°C - 15.00°C = 10.00°C)

Replacing:

Q = -45.00*4.184J/g°C*10.00°C

Q = -1882J

Right answer is:

Answer:

hope it helps you.......

Answer:

B

Explanation:

No explanation needed for it i got 100% on it

Lifting the remains is the last step in the excavation of the skeletal remains. Therefore, option E is correct.

In archaeology, excavation can be described as the exposure, processing, and recording of archaeological remains. An excavation site or "dig" can be the area being studied. These locations are from one to various areas at a time while a project can be conducted over weeks to several years.

Excavation involves the recovery of various types of data from a site. This data includes ecofacts, artifacts, features, and archaeological context. Before excavating, the presence of remains can often be suggested by remote sensings, such as ground-penetrating radar.

During excavation, stratigraphic excavation removes phases of the site one layer at a time and keeps the timeline of the material remains consistent. This is done through mechanical means and the soil is processed via methods like mechanical sieving or water flotation.

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Answer:

a marble about to reach the bottom of the slope

Explanation:

hope this helps

Answer:

Compounds

Explanation:

It is a compound when they are separated by chemical bonds.

Compound are substances composed of two or more kinds of atoms that are joined together in a definite grouping.

The properties of a compound are distinct and different from those of the individual elements that are combined in its make-up.

Within a compound there are chemical bonds.

The given question is incomplete. the complete question is:

Write the net ionic equation for the reaction [tex]2AgNO_3(aq)+(NH_4)_2CO_3(aq)->Ag_2CO_3(s)+2NH_4NO_3(aq)[/tex]

Answer:  [tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]

Explanation:

Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.

The given chemical equation is:

[tex]2AgNO_3(aq)+(NH_4)_2CO_3(aq)->Ag_2CO_3(s)+2NH_4NO_3(aq)[/tex]

The complete ionic equation is:

[tex]2Ag^+(aq)+2NO_3^-(aq)+2NH_4^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)+2NH_4^+(aq)+2NO_3^-(aq)[/tex]

The ions which are present on both the sides of the equation are ammonium and nitrate ions and hence are not involved in net ionic equation.

Hence, the net ionic equation is [tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]

Answer:

[tex]E=1.48x10^4J[/tex]

Explanation:

Hello!

In this case, since the energy implied in a heating process is computed by using the following equation:

[tex]E=mC(T_f-T_i)[/tex]

Whereas m is the mass, C the specific heat and T the temperature. In such a way, by plugging in the given mass, specific heat and temperatures, we obtain the following energy:

[tex]E=187.0g*4.703\frac{J}{g\°C} (52.9\°C-36.1\°C)\\\\E=1.48x10^4J[/tex]

Considering that the specific heat can by used by unit of °C or K because their difference is equivalent.

Regards!

Answer:

False

Explanation:

Water is said to have a higher heat capacity than soil and stones, so the ocean takes much longer to heat and to cool than the land. 2. Coastal areas have more moderate temperatures than landlocked areas because of the heat capacity of the ocean and hence the answer is false.

Answer:

False.

Explanation:

Answer:

264.28 L of CO₂

Explanation:

We'll begin by calculating the number of moles present in 275 g of NO₃¯. This can be obtained as follow:

Mass of NO₃¯ = 275 g

Molar mass of NO₃¯ = 14 + (16×3) = 14 + 48 = 62 g/mol

Mole of NO₃¯ =?

Mole = mass / molar mass

Mole of NO₃¯ = 275 / 62

Mole of NO₃¯ = 4.44 moles

Next, we shall determine the number of mole of CO₂ produced from the reaction. This can be obtained as follow:

2NO₃¯ + 5CO + 2H⁺ —> N₂ + H₂O + 5CO₂

From the balanced equation above,

2 moles of NO₃¯ reacted to produced 5 moles of CO₂.

Therefore, 4.44 moles of NO₃¯ will react to produce = (4.44 × 5) / 2 = 11.1 moles of CO₂.

Thus, 11.1 moles of CO₂ were produced from the reaction.

Finally, we shall determine the volume of CO₂ produced each day. This can be obtained as follow:

Temperature (T) = 17 °C = 17 °C + 273 = 290 K

Pressure (P) = 1 atm

Number of mole (n) of CO₂ = 11.1 moles

Gas constant (R) = 0.0821 atm.L/Kmol

Volume (V) of CO₂ =?

PV = nRT

1 × V = 11.1 × 0.0821 × 290

V = 264.28 L

Thus, 264.28 L of CO₂ would be produced each day.

The volume of [tex]\rm CO_2[/tex] produced has been 264.28 L.

The volume of the carbon dioxide gas produced can be calculated with the ideal gas equation.

The moles of [tex]\rm NO_3^-[/tex] has been:

Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]

Moles of 275 g  [tex]\rm NO_3^-[/tex] has been:

Moles = [tex]\rm \dfrac{275}{62}[/tex]

Moles of  [tex]\rm NO_3^-[/tex] = 4.44 moles

The balanced equation gives that with the reaction of 2 moles [tex]\rm NO_3^-[/tex] , 5 moles carbon dioxide has been formed.

Moles of carbon dioxide formed with 4.44 mol [tex]\rm NO_3^-[/tex] has been:

2 moles [tex]\rm NO_3^-[/tex] = 5 moles [tex]\rm CO_2[/tex]

4.44 moles [tex]\rm NO_3^-[/tex]  = 11.1 moles [tex]\rm CO_2[/tex].

The volume of the [tex]\rm CO_2[/tex] can be calculated as:

Pressure [tex]\times[/tex] Volume = moles [tex]\times[/tex] Rydberg constant [tex]\times[/tex] temperature

For the [tex]\rm CO_2[/tex] produced:

1 atm [tex]\times[/tex] Volume = 11.1 mol [tex]\times[/tex] 0.0821 atm.L/K.mol [tex]\times[/tex] 290 K

Volume = 264.28 L.

The volume of [tex]\rm CO_2[/tex] produced has been 264.28 L.

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Answer:

1 Oxygen atom has a mass of 16 grams, thus diatomic oxygen weights twice as much- 32 grams. Hence 32 grams is needed.

Answer:

the gravity

Explanation:

i hope you help this answer

Answer:

the ocean

Explanation:

Answer:

independent varible

Explanation:

Answer:

You need to convert 27.8 miles to km and gallon to liters, then

(km/L) x #L = ?

27.8×112

=?

?×1gal

=?

?×1mi

=?

=?×?×?

answer

Answer:

per day means - and if means + and of means × lmk if u need help

Answer:

yes thats right

Explanation:

Answer:

33 km in 3 hours

11/1= 11

11*3=33

Explanation:

Answer:

the metal melts and floats

Explanation:

When potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame.

Answer:

It reacts rapidly to form a colorless solution of potassium hydroxide.

Explanation:

Potassium metal reacts very rapidly with water to form a colorless basic solution of potassium hydroxide (KOH) and hydrogen gas (H 2). The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic.

Answer:Metallic and covalent bonds are strongly attractive; hydrogen

bonding and Van der Waals forces are weakly attractive.

Answer:

Metallic and covalent bonds are strongly attractive; hydrogen bonding and Van der Waals forces are weakly attractive..

trust me i just did it

Explanation:

Answer:

of 7 I guess the and is 2 I don't know anything about 8

The valence of lead is 4.

Hence the name of the compound is called Lead (IV) oxide.

Given

PbO₂ compound

Required

The valence of Pb

Solution

The oxidation number of element O in the compound = -2, except for OF₂ the oxidation state = + 2 and the peroxides (Na₂O₂, BaO₂) the oxidation state = -1 and superoxide, for example KO₂ = -1/2.

The oxidation state in the uncharged compound = 0,

So The oxidation state of Pb :

Pb + 2.(-2) = 0

Pb - 4 = 0

Pb = +4

Answer:1.8 moles Fe and 2.7 moles CO2

Explanation:

Answer:

1.8 moles Fe and 2.7 moles CO2

Answer: 31.8 g

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]    

[tex]\text{Moles of} Al_2O_3=\frac{60.0g}{102g/mol}=0.59moles[/tex]

[tex]\text{Moles of} C=\frac{30.0g}{12g/mol}=2.5moles[/tex]

[tex]Al_2O_3+3C\rightarrow 2Al+3CO[/tex]  

According to stoichiometry :

1 mole of [tex]Al_2O_3[/tex] require 3 moles of [tex]C[/tex]

Thus 0.59 moles of [tex]Al_2O_3[/tex] will require=[tex]\frac{3}{1}\times 0.59=1.77moles[/tex]  of [tex]C[/tex]

Thus [tex]Al_2O_3[/tex] is the limiting reagent as it limits the formation of product and [tex]C[/tex] is the excess reagent as it is present in more amount than required.

As 1 mole of [tex]Al_2O_3[/tex] give = 2 moles of [tex]Al[/tex]

Thus 0.59 moles of [tex]Al_2O_3[/tex] give =[tex]\frac{2}{1}\times 0.59=1.18moles[/tex]  of [tex]Al[/tex]

Mass of [tex]Al=moles\times {\text {Molar mass}}=1.18moles\times 27g/mol=31.8g[/tex]

Thus 31.8 g of [tex]Al[/tex] will be produced from the given masses of both reactants.