Read the given expression.
Effective nuclear charge = atomic number - x
Which of the following explains the identity of X and its trends across a period? (5 points)
X is the screening constant, and it increases across a period.
X is the screening constant, and it remains constant across a period.
X is the number of outermost electrons, and it increases across a period.
X is the number of outermost electrons, and it remains constant across a period.

Answers

Answer 1

Answer:

Option 2: X is the screening constant, & it remains constant across a period.

Explanation:

I took the test and got the question correct :)

Answer 2

As we move across the period, X is the screening constant, and it remains constant across a period.

As we move across the period, the size of atoms become smaller because of an increase in the size of the nuclear charge. This leads to a decrease in atomic radius.

As the size of atom decreases, the screening effect on the outermost electron decreases accordingly. Hence, as we move across the period, X is the screening constant, and it remains constant across a period. This is because, no new shells are added across the period.

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Related Questions

Why are models used to represent atoms?
O A. Atoms are too small to see.
O B. Models are completely accurate.
O C. Models explain new evidence.
O D. Models never change over time.

Answers

A because that is ture and we use a model of the atom to explain what an atom does
A. We can’t see actual atoms, so we use bigger models to grasp more information

What is the IUPAC name for Ester with 9 carbon atoms ?

Answers

Explanation:

[tex]CH _{3}CH _{2}COOCH _{2} CH _{2}CH _{2}CH _{2}CH _{2}CH _{3}[/tex]

NAME: Hexylpropenoate

What is the standard cell notation of a galvanic cell made with zinc and gold?
A. Zn2+(aq) | Zn(s) || Au(s) | Au+(aq)
B. Au(s)| Aut(aq) || Zn2+(aq) | Zn(s)
C. Aut (aq)| Au(s) || Zn(s) | Zn2+(aq)
D. Zn(s) | Zn2+ (aq) || Aut(aq) | Au(s)

Answers

Answer:

D

Explanation:

Conservation of matter means that:
55
Matter is never created nor destroyed.
Matter is always created and destroyed.
Matter always turns into energy
Matter is flexible, it can be created destroyed, or turned into energy

Answers

Answer:

Matter is never created or destroyed

True or False: The moon's gravity affects the oceans nearest the moon because the moon's gravity pulls water into a tidal bulge.

Answers

Answer: The moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides

Explanation:

The moon's gravity affects the oceans nearest the moon because the moon's gravity pulls water into a tidal bulge is a true statement.

What is tidal force?

The tidal force is the result of the moon's gravitational pull.

The tidal force causes Earth—and its water—to bulge out on its closest and furthest sides from the moon. High tides cause these water bulges.

Thus, the statement is correct.

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What is the mass of oxygen gas (O2) needed when 8.75 x 1070 molecules of methane (CH4) combust to form carbon dioxide (CO2)? (Choose closest answer)
CH4 + 2O2 -> CO2(g) + 2H2O
A.
8.43 x 1093 grams
B.
9.299 x 1048 grams
C.
2.32 x 103 grams
D.
9.08 grams
E.
my mom

Answers

it’s so easy it’s d then the carbon dioxide msmsnansnsnsjs

A dog runs 6 km in 30 minutes. What is the dog’s average speed in km/h?

Answers

here's your solution

==> distance covered = 6 km

==> time taken = 30 min

==> time in hour = 30/60 = 1/2hr

= speed = distance/time

==> speed = (6)/(1/2)

==> speed = 12 km/hr

hope it helps

When a dog run 6 km in 30 minutes then dogs average speed will be 12 km/h.

What is average speed?

The average speed of something is computed by dividing the number distance travelled by the total time it took to travel that distance. Average speed can be determined by the formula:

V=d/T

where, V is average speed , d is distance and T is time.

It is given that , d= 6 km and T= 30 minutes(0.5 h).

Calculation of average speed is show below:

Now, puts the value of given data in average speed formula.

Average speed(V )= 6/ 0.5 = 12 km/h

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A gas is held at 120.4 kPa and 333K. When the temperature is decreased to
275K at a constant volume, calculate the new pressure in the container.
Type your answer with the correct number of sig figs and units. *

Help please 100 points!!

Answers

Answer:

....

Explanation:

Set up the conversion chart below to find how many molecules are in 4.6 moles of ammonium nitrate (NH4NO3
)?

Answers

Answer: There are [tex]27.701 \times 10^{23}[/tex] molecules in 4.6 moles of ammonium nitrate [tex](NH_{4}NO_{3})[/tex].

Explanation:

According to the mole concept, there are [tex]6.022 \times 10^{23}[/tex] molecules present in 1 mole of every substance.

Hence, the number of molecules present in 4.6 moles of ammonium nitrate are calculated as follows.

[tex]4.6 \times 6.022 \times 10^{23}\\= 27.701 \times 10^{23} molecules[/tex]

Thus, we can conclude that there are [tex]27.701 \times 10^{23}[/tex] molecules in 4.6 moles of ammonium nitrate [tex](NH_{4}NO_{3})[/tex].

A gas has a volume of 1.22L at 179K. Once heated, the same gas now has a volume of 6.1L at 285K and 1.34atm. What was the original pressure of the gas?

Answers

here is your answer the question for the combined gas laws

If you start with 6 moles of N2 and 6 moles of H2 (meaning you won't have enough of 1 of the ingredients), how many moles of NH3 would you be able to make?

Answers

Answer:

[tex]4molNH_3[/tex]

Explanation:

Hello there!

In this case, according to the given information it will be firstly necessary to set up the chemical equation taking place:

[tex]N_2+3H_3\rightarrow 2NH_3[/tex]

We infer we need to calculate the moles of NH3 by using both of the moles of N2 and H2 at the beginning, in order to identify the limiting reactant:

[tex]n_{NH_3}=6molN_2*\frac{2molNH_3}{1molN_2}=12molNH_3\\\\ n_{NH_3}=6molH_2*\frac{2molNH_3}{3molH_2}=4molNH_3\\[/tex]

Thus, since hydrogen yields the fewest moles of ammonia, we conclude that we are just able to yield 4 moles of NH3.

Regards!

The same amount of heat is added to a 10-g sample of each of the following metals. If each metal is initially at 20.0°C, which metal will reach the highest temperature? show your work
A. gold 0.129 J/(g °C)
B. beryllium 1.82 J/(g °C)
C. calcium 0.653 J/(g °C)
D. copper 0.385 J/(g °C)

Answers

Answer: A

Explanation:

A

Heat is the product of the mass, specific heat, and delta temperature. The gold metal will reach the highest temperature. Thus, option A is correct.

What is specific heat?

Specific heat (c) is the heat required by a substance to get heated a unit mass by a unit of temperature. The specific heat is given as,

[tex]\rm c = \rm \dfrac{Q}{m \times \Delta T}[/tex]

Here, Q is the heat applied, m is the sample's mass and delta T is the change in the temperature.

The value of heat applied is the same for all the metals, so a change in temperature is calculated as,

[tex]\rm \Delta T = \rm \dfrac{Q}{c . m }[/tex]

From this, it can be said that the temperature is inversely related to the specific heat of the metal and hence the metal having the smallest c will have the highest change in the temperature.

Therefore, gold (c = 0.129 J/(g°C)) will reach the highest temperature.

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. Which of the following is not a product of photosynthesis?

O A. Carbon dioxide
O B. Glucose
O C. Oxygen​

Answers

Answer:

The answer would be a

Explanation:

That is what goes into the plant and oxygen IS an outcome

2H2 + O2 → 2H2O
"PLEASE HELP ASAP"
Which of the following statements would be correct if one mole of hydrogen was used in this reaction? (5 points)
One mole of oxygen was used in this reaction.
Two moles of oxygen were used in this reaction.
One mole of water was produced from this reaction.
Two moles of water were produced from this reaction.

Answers

Answer:

- One mole of oxygen was used in this reaction.

- Two moles of water were produced from this reaction.

Explanation:

In addition: - Two moles of hydrogen were used.

Given the data from the question, the correct statement is:

One mole of water, H₂O was produced from the reaction

Basic concept

To know which options are correct, we shall determine the number of mole of O₂ used and the number of mole of H₂O produced.

How to determine the mole of  O₂ used

Balanced equation

2H₂ + O₂ —> 2H₂O

From the balanced equation above,

2 moles of H₂ required 1 mole of O₂

Therefore,

1 mole of H₂ will require = 1 / 2 = 0.5 mole of O₂

Thus, 0.5 mole of O₂ is needed for the reaction

How to determine the mole of H₂O produced

From the balanced equation above,

2 moles of H₂ reacted to produce 2 moles of H₂O

Therefore,

1 mole of H₂ will also react to to produce 1 mole of H₂O

Thus, 1 mole of H₂O was produced from the reaction.

SUMMARY

When 1 mole of H₂ was used in the reaction,

0.5 mole of O₂ was used 1 mole of H₂O was produced

Considering the options given in the question above, the correct statement is:

1 mole of H₂O was produced

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Can someone pls tell what to put in 6 and 7 pls no links ???

Answers

Bases feel slippery and for number 7 the type of solution is acidic :)

15.0 g of potassium chlorate is melted so that it will then decompose. What mass of oxygen is produced assuming all of the original potassium chlorates fully decomposes?

Answers

Answer:

5.875 g of Oxygen

Explanation:

We must first balance our decomposition equation KClO3 -> K + ClO3

The amount of oxygen in CLO3 is 3 times the original. We begin by converting 15g of KClO3 to moles. 15 / (39.1 + 35.45 + 3(16) ) = 0.122 mols.

Then we go to moles of oxygen,

.122 * 3 = 0.367 mols of Oxygen

Then to grams of Oxygen

.367 * 16 = 5.875 g

Find the force of an object that has an acceleration of 6.7 m/s2 and a mass of 12 kg.

Answers

it would be 80.4 newtons

Question 1
A molecule contains carbon, hydrogen and oxygen. For every carbon atom there are
twice as many hydrogen atoms but the same number of oxygen atoms.
What is the formula of the molecule?
А
CH 0
B
C2H4O2
C
C,H,O2
D
C,H,O2

Answers

The required molecule is :

=》option B.) C2H4O2

it has 2 carbon atoms, 4 hydrogen atoms which it twice the number of carbon atoms and 2 oxygen atoms same as carbon.

Given the balanced equation representing a reaction:
H2SO3 + H2O « H3O+ + HSO3-
According to one acid-base theory, the H2SO3 molecules act as (AKS 5g)

Answers

Answer:

An acid because they donate H^+ ions

Explanation:

Let us look at the equation again;

H2SO3 + H2O « H3O+ + HSO3-

An acid donates hydrogen ion while a base accepts hydrogen ion. Hence, we have to look at which species that acted as hydrogen ion donors or acceptors.

We can clearly see that H2SO3 acted as a hydrogen ion donor while H2O acted as a hydrogen ion acceptor.

Thus, H2SO3  acted as an acid by donating hydrogen ions.

If an object is not accelerating, you can be sure that
A. its speed is 0 m/s.
B. it has a mass of 0 kg.
c. the net force acting on it is O N.

Answers

Answer:

A

Explanation:

It's not moving so it would be going 0 meters per second

Answer:

I think its A

Explanation:

Please help it’s my final

Answers

I believe the answer is 80 because if you find 50 on the y axis and trail it to the x axis it intersects at 80

how many moles are there in 302 grams of Ca2N2

Answers

Answer:

2.0371352212585085

Explanation:

4) When solid sodium nitrate is heated, solid sodium nitrite and oxygen gas
(02) are produced. Write the balanced chemical equation for this chemical
reaction using the correct chemical formulas and include conditions (s, l, g, or
aq). Put your answer in the box below.

Write the balanced chemical equation and state what type of chemical reaction this is.

Answers

Answer: The balanced chemical equation is [tex]2NaNO_{3}(s) + Heat \rightarrow 2NaNO_{2}(s) + O_{2}(g)[/tex] and it is a decomposition chemical reaction.

Explanation:

A chemical reaction in which single compound is decomposed into two or more species is called a decomposition reaction.

For example, [tex]NaNO_{3}(s) + Heat \rightarrow NaNO_{2}(s) + O_{2}(g)[/tex]

As the compound [tex]NaNO_{3}[/tex] is decomposing to given two different substances. So, it is a decomposition reaction.

Here, the number of atoms on reactant side are as follows.

Na = 1N = 1O = 3

The number of atoms on product side are as follows.

Na = 1N = 1O = 4

To balance this equation, multiply [tex]NaNO_{3}[/tex] by 2 on reactant side and multiply  [tex]NaNO_{2}[/tex] by 2 on product side. Therefore, the equation will be rewritten as follows.

[tex]2NaNO_{3}(s) + Heat \rightarrow 2NaNO_{2}(s) + O_{2}(g)[/tex]

Here, number of atoms on reactant side are as follows.

Na = 2N = 2O = 6

The number of atoms on product side are as follows.

Na = 2N = 2O = 6

Hence, this equation is balanced.

Thus, we can conclude that the balanced chemical equation is [tex]2NaNO_{3}(s) + Heat \rightarrow 2NaNO_{2}(s) + O_{2}(g)[/tex] and it is a decomposition chemical reaction.

when 3.18g of copper(ii)oxide was carefully heated in a stream of dry hydrogen, 2.54g of copper and 0.72g of water was formed. Determine the number of moles of hydrogen atoms which combine with one mole of oxygen atoms. Show your working.

Answers

Answer:

hsbdgjvejsnshns gzjs svshs

Molecules are always in motion. True False

Answers

Answer: FALSE

Explanation:

how many moles of iron are in 4.8 x 10^24 atoms of iron

Answers

Answer:

7.97 moles

Explanation:

The number of moles (n) of iron (Fe) in this question can be calculated by dividing its number of atoms by Avogadro's number (6.02 × 10²³ atoms).

That is;

n = number of molecule ÷ Avogadro's number

According to this question, the number of atoms of Fe is given as 4.8 x 10²⁴ atoms.

Hence,

n = 4.8 x 10²⁴ ÷ 6.02 × 10²³

n = 4.8/6.02 × 10^(24-23)

n = 0.797 × 10¹

n = 7.97 moles

Characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices. (1) Electron loss is always associated with an increase in oxidation number. (2) An exothermic reaction occurs when the energy required to break bonds in reactants is less than the energy released by bond formation in the products. (3) The concentrations of pure liquids and pure solids are never included in an equilibrium constant expression because such concentrations never change.

Answers

Answer:

Electron loss is always associated with an increase in oxidation number- True

An exothermic reaction occurs when the energy required to break bonds in reactants is less than the energy released by bond formation in the products.  True

The concentrations of pure liquids and pure solids are never included in an equilibrium constant expression because such concentrations never change. True

Explanation:

Oxidation implies loss of electrons. When a specie looses electrons, its oxidation number increases. For instance; Fe(s) -----> Fe^2+(aq) + 2e implies an increase in oxidation number of Fe from 0 to +2.

In an exothermic reaction, the energy required to break the bonds in the reactants is less than the energy released when new bonds form in the products.

We do not include the concentrations of pure liquids and pure solids in the equilibrium constant expression because the concentration of these do not change significantly throughout the reaction.

Use the drop-down menus to match the alkanes with the correct name.

CH3CH2CH2CH2CH2CH2CH2CH3

CH3CH2CH2CH3

CH4
CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

CH3CH3


the answers are :
octane
butane
methane
decane
ethane

Answers

Answer:

✔ octane

CH3CH2CH2CH2CH2CH2CH2CH3

✔ butane

CH3CH2CH2CH3

✔ methane

CH4

✔ decane

CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

✔ ethane

CH3CH3

Explanation:

An alkane contains only carbon and hydrogen. The following are the accurate names of the compounds;

CH3CH2CH2CH2CH2CH2CH2CH3 - octaneCH3CH2CH2CH3 - butaneCH4 - methaneCH3CH2CH2CH2CH2CH2CH2CH2CH2CH3 - decaneCH3CH3 - ethane

What is an alkane?

An alkane is a compound whose only functional group is the carbon - carbon single bond. This compounds contain only carbon and hydrogen.

The correct names of the compounds are;

CH3CH2CH2CH2CH2CH2CH2CH3 - octane

CH3CH2CH2CH3 - butane

CH4 - methane

CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3 - decane

CH3CH3 - ethane

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Which illustration represents a sound wave?


A or B

no link or i will report,plz help this is a test

Answers

The answer is B because of the compression and expansion

PLEASE HELP! NO LINKS! CHEMISTRY!
Solution A has a pH of 2.0. Solution B has a pH of 5.0. Which solution is more acidic? Based on the H+ ion concentrations in the two solutions, how many times more acidic?

Answers

Answer:

Solution A is 1,000 times more acidic than Sol. B

Explanation:

for pH values we use scientific notation:

-log10 c (where c is the hydrogen ion concentration) is used to notate pH value (think of it as a unit)

ie:

10^-2 is sol A 10^-5 is sol B

5-2 is 3

10^-3 = 1000

there's a diff of 1,000 between the solutions.

The acidity or alkalinity of a solution depends on the hydronium ion concentration and hydroxide ion concentration. Here the solution A of pH 2.0 is more acidic than the solution of pH 5.0.

What is pH?

The pH of a solution is defined as the negative logarithm to the base 10 of the value of the hydronium ion concentration in moles per litre. When the pH of the solution is less than 7 it is acidic whereas when pH is greater than 7, it will be basic.

The pH of the solution is calculated by the equation:

pH = - log [H₃O⁺]

Then the concentration of H₃O⁺ is:

[H₃O⁺] = 10⁻pH

At pH = 2.0, [H₃O⁺] = 10⁻² = 0.01

At pH = 5.0, [H₃O⁺] = 10⁻⁵ = 0.00001

Thus here the Solution A is 1,000 times more acidic than Solution B.

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