1. State the general period and group trends among
main-group elements with respect to each of the
following properties:
a. atomic radii
b. first ionization energy
c. electron affinity
d. ionic radii
e. electronegativity
2. a. In general, how do the periodic properties of
the d-block elements compare with those of
the main-group elements?
b. Explain the comparison made in (a).​​
3. For each main-group element, what is the
relationship between its group number and
the number of valence electrons that the group
members have?


PLEASE HELP FAST

Answer:

Explanation:

Here, we want to get which of the compounds have the highest percentage by mass of nitrogen

What we have to do here is to divide the mass of nitrogen atoms in the compound by the molecular mass of the compound

a) NH3

The atomic mass of nitrogen is 14 amu, the atomic mass of hydrogen is 1 amu

The molar mass is thus 14 + 3(1) = 17 g/mol

The percentage by mass of nitrogen will be

14/17 * 100 = 82.35 %

b) HCN

The atomic mass of carbon is 12 amu

Thus, we have the molar mass as

1 + 12 + 14 = 27 g/mol

Percentage of nitrogen by mass will be : 14/27 * 100 = 51.85 %

c) For N2O

The atomic mass of oxygen is 16 amu

The molar mass of the compound will be 14(2) + 16 = 44 g/mol

Percentage of nitrogen by mass will be = 28/44 * 100 = 63.64 %

d) NI3

The atomic mass of iodine is 127 g/mol

So the molar mass of the compound will be:

14 + 3(127) = 395 g/mol

Percentage by mass of nutrogen will be

14/395 * 100 = 3.54 %

From what we have, the highest percentage by mass of nitrogen is 82.35 % and that belongs to ammonia (NH3)

Metallic solids,

the atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties. All exhibit high thermal and electrical conductivity, metallic luster, and malleability.

Answer: c. metallic

Answer:

HS is stripped from each O.

The concentration of the unknown weak acid solution is 0.228 M.

Acid dissociation constant, K a K text a Ka, and weak acids. Acids that don't entirely dissociate in solution are referred to as weak acids. In other words, any acid that is not a strong acid qualifies as a weak acid. The amount of dissociation determines how strong an acid is; the more dissociation, the stronger the acid.

Equivalent point:

Since the volume is 4.00 mL of the weak acid, and it takes  18.3 mL of 0.0500 M NaOH to reach the equivalence point.

We know that

In the equivalence point, [H⁺] = [OH⁻].

here the given formula C₁V₁=C₂V₂ is used

Here

C₁ = 0.0500 M

V₁ = 18.3 mL

C₂ = ?

V₂ = 4.00 mL

So, the C₂ is

0.0500 M * 18.3mL = C₂ * 4.00 mL

C₂ = 0.228M

The concentration of the unknown weak acid solution is 0.228 M

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Atomic number. should be 120.

due to.... a/q

Alkaline earth metals are part of the eighth group and are known to exist in two groups.

Consequently, the element's atomic number will be 120.

The quantity of protons in an atom's nucleus is known as the atomic number. An element's identity is determined by its proton count (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).

A chemical element's atomic number is its position in the periodic system, which places the elements in ascending order of the number of protons in their nuclei. As a result, the atomic number is also determined by the number of protons, which is always equal to the number of electrons in a neutral atom.

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What's phase diagram?

The phase diagram is a pressure vs temperature sketch. On the graph, the different physical states of any system at variable temperature and pressure are shown.

What's a Triple point?

A triple point is the point on a phase diagram where all three states of a system (solid, liquid, and gas) are in equilibrium.

What's a Critical point?

A critical point is that point on the phase diagram where the boundary between the liquid phase and gaseous phase vanishes away.

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Answer:

use a tumbler to cover a candle that is burning, after a few minutes it turns off automatically without any external forces due to the absence of oxygen

Explanation:

When monosaccharides are bonded together c) all of these are correct.

Monosaccharides can be described as sugars from which all other complex forms of sugars are formed. Monosaccharides are the simplest form of sugars the combination of which leads to the formation of disaccharides, polysaccharides and oligosaccharides.

When the monosaccharides join in order to form complex sugar molecules, a single molecule of water is lost by each new link or joining of molecules that occur.

As monosaccharides are simplest of sugars, they are more easily absorbed as compared to other types of sugars.

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Answer:

Explanation:

To find the number of entities in a given substance we use the formula

N = n × L

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question

n = 2.5 moles

We have

N = 2.5 × 6.02 × 10²³ = 1.505 × 10²⁴

We have the final answer as

Hope this helps you

The reactant will be potassium iodide and lead (ii) nitrate. The products will be lead (ii) iodide and potassium nitrate.

In the field of chemistry, reactants can be described as starting materials that react together in order to form a product. The reactants are the starting material whereas the products are the ending material.

In the case above, potassium iodide and lead (ii) nitrate are the reacting materials as they are the starting materials. On the other hand, lead (ii) iodide and potassium nitrate are the ending products of this reaction.

While writing a chemical equation, the reactants are written on the left-hand side, before an arrow. On the other hand, the products are written on the right-hand side after the arrow.

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The chromatography experiment which would best decide whether the compounds are identical or not is to Repeat the original experiment once more with various solvent systems;

If two things have the same Rf value, they are probably the same compound, but not always. They are definitely distinct compounds if their Rf values differ.

Compounds with a low polarity have higher Rf values than compounds with higher polarity. Compounds' absorptivity typically rises in tandem with their polarity—that is, the more polar a compound is, the more strongly it binds to the adsorbent. Solvents' eluting power increases with polarity. In diverse solvents, different compounds with identical Rf values might behave differently.

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To make a 100 ml solution of 0.8 m from a 2.7 m concentrated stock solution we have to take a volume of: 30 ml of the concentrated solution

To solve this problem, the formula and the procedure that we have to use is:

c1 * v1 = c2 * v2

Where:

Information about the problem:

Applying the dissolution of concentrations formula and clearing the volume of the concentrated solution (v1) we get:

c1 * v1 = c2 * v2

v1 = (c2 * v2)/ c1

v1 = (0.8 m * 100 ml)/ 2.7 m

v1= 29.6 ml

By rounding the volume to a whole integer value we have:

v1= 30 ml

In chemistry a solution is known as a homogeneous mixture of two or more components called:

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Answer:

Gold

Explanation:

To recognize what element this is, we can simply look at the last orbital (5d9) and go to the periodic table and see what element is in that final orbital.

We go to row 6 (because of the 6s orbital at the beginning of this row) and then we see that our 6s orbital is full with 2 electrons, then our 4f orbital is full with 14 electrons, and our 5d orbital is not full where we only have 9 electrons instead of 10.

We then go to our 5d orbital and count 9 times into that orbital and end up with our final element being Gold (Au).

Ba(OH)2(aq) + 2HNO3(aq) ==> 2H2O(l) + Ba(NO3)2(aq)  ...  balanced equation

A chemical equation that is balanced has the same number of each type of atom on both sides of the equation. Subscripts are a component of the chemical formulas for the reactants and products that show how many atoms of the previous element there are in each.

note the stoichiometry ...  2 mols HNO3 for each 1 mol Ba(OH)2

Now we can use dimensional analysis and the noted stoichiometry to solve the problem:

32.0 ml HNO3 x 1 L/1000 ml x 0.200 mol / L = 0.0064 mols HNO3 used

0.0064 mol HNO3 x 1 mol Ba(OH)2 / 2 mols HNO3 = 0.0032 mol Ba(OH)2 present

Concentration of Ba(OH)2 = mols/L = 0.0032 mols / 0.0250 L = 0.128 M

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The enzyme that catalyzes the synthesis of ATP as hydrogen ions flow down their concentration gradient is called ATP synthase.

In the inner mitochondriаl membrаne, hydrogen ions hаve just one chаnnel аvаilаble: а membrаne-spаnning protein known аs АTP synthаse. Conceptuаlly, АTP synthаse is а lot like а turbine in а hydroelectric power plаnt. Insteаd of being turned by wаter, it’s turned by the flow of hydrogen ions moving down their electrochemicаl grаdient. Аs АTP synthаse turns, it cаtаlyzes the аddition of а phosphаte to АDP, cаpturing energy from the proton grаdient аs АTP.

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Answer:

it would be the same weight but it's ith sugar I think it would way more

1.5 atm pressure will be required for neon at 30°C to have the same density as nitrogen at 20°C and 1.0 atm.

The relationship between a gas's pressure P, volume V, and temperature T in the range of low pressures and high temperatures, when the gas's molecules move virtually independently of one another, is known as the ideal gas law, also known as the perfect gas law.

T[tex]_N_e[/tex]​ =30⁰C=(30+273)K=303K

T[tex]_N_2[/tex]​​ =20⁰C=(20+273)K=293K

P[tex]_N_2[/tex] ​ =1.0atm

Ideal gas constant - R=0.0821L⋅atm/ K⋅ mol

The molar mass of

Neon - M[tex]_N_e[/tex]​​=20.18g/mol

Nitrogen - M[tex]_N_2[/tex]​​ ​ =2⋅14.007g/mol=28.014g/mol

Determine the pressure P[tex]_N_e[/tex]​  required for neon at 30⁰C to have the same density (d) as nitrogen at 20⁰C.

d = m/V

We know that

n = m/M

Using the ideal gas law, we get

PV = nRT

PV = m/M *RT

Since

PM/RT = m/V =d

d =  PM/RT

d= [tex]\frac{P_{N_2} M_{N_2}}{R T_{N_2}}[/tex]

d = 1.0 atm * 28.014 g/mol/0.0821L atm/K mol 293K

d = 1.2 g//L

Since both gases have the same density, we can calculate the pressure of neon gas, using

[tex]d=\frac{P_{N e} M_{N e}}{R T_{N e}}[/tex]

[tex]P_{N e}=\frac{d R T_{N e}}{M_{N e}}[/tex]

[tex]P_{N e}[/tex]=1.2g/L . 0.0821L . atm/K.mol.303 K/20.18 g/mol

[tex]P_{N e}[/tex]=1.5 atm

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Answer:

There are 400 meters in a hectometer?

Explanation:

Answer:

there are 400 meters in a hectometer?

Explanation:

Answer:

C. high ionization energy and high electronegativity

Explanation:

When an electron is gained or lost from an atom or a molecule, an ion is formed. When a molecule or atom gains electrons, anions (which are negatively charged ions) are formed.

An example of positive feedback in the human body may be the increased production of a hormone in response to the products of the same hormone, a stimulus is a reaction produced as a consequence of a change in the environment, while a response impacts the stimulus to maintain homeostasis.

The expression positive feedback is used in biology to explain the output of a process that may feed the input of the same biological process, such as occurs when a hormone is synthesized depending on the concentration of its hormonal product.

Moreover, a stimulus is a change in conditions that surround an organism and it leads to a concomitant response to maintain the state of equilibrium which is referred to as homeostasis.

Therefore, with this data, we can see that homeostasis and stimulus are interrelated, which positive feedback is a response as the output of the same process.

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Based on the Principle of Complementary Colors , the  colors and wavelengths expected to be the most strongly absorbed by cu 2+ ions are :-

Orange  : 600–640 nm

Blue       : 450–480 nm

Violet      :400–450 nm  

Green     : 450–560 nm

Red         : 640–700 nm

Yellow      : 560–600 nm

Complementary color are pairs of colors which, while blended or mixed, cancel every different out (lose hue) via generating a grayscale color like white or black. whilst located next to every other, they devise the most powerful contrast for those  colours. Complementary colours may also be known as "opposite colorings".

The RGB coloration version, invented inside the 19th century and absolutely advanced inside the twentieth century, uses combos of pink, inexperienced, and blue mild towards a black heritage to make the colours visible on a computer monitor or television display. Within the RGB version, the primary colors are purple, green, and blue. The complementary number one–secondary combinations are crimson–cyan, inexperienced–magenta, and blue–yellow. Inside the RGB colour version, the mild of  complementary shades, consisting of pink and cyan, combined at full depth, will make white mild, for the reason that  complementary hues comprise mild with the whole variety of the spectrum. If the light isn't always completely severe, the resulting mild will be gray.

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The conjugate base of a compound is what this compound will be after donating a H⁺.

The comopund in question is H₂BO₃⁻. After it loses 1 H⁺, it will have one less H atom and its charge decrease by one. Its charge is only with a "-" sign, which means its chargeis 1-. After decreasing by one, the charge becomes 2-.

So, the conjugate base will be HBO₃²⁻

Answer:

MnO

Explanation:

See the attachwed worksheet

The value into kilocalories up to three significant figures is 77.1 x 10^3 kilocalories

1 kj = 0.239 kilocalorie

3.23 x 10^6 kJ x 0.239 kilocalorie = 77.1 x 10^3 kilocalories

3.23 x 10^6 kJ = 77.1 x 10^3 kilocalories

In chemistry, Significant figures are the digits of value which carry meaning towards the resolution of the measurement. They are also called significant figures in chemistry. All the experimental measurements have some kind of uncertainty associated with them.

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The strong attractive forces in ionic crystal make them rigid , hard and brittle solid.

Ionic crystal are so strong because of the strong attractive forces between ions . Ionic compound formed between a positively charged ion and a negatively charged ion , the bond between them are so strong that make ionic crystal brittle. and also make it rigid.  the presence of strong electrostatic force of attraction make the ionic crystal so hard. Due to the non directional nature of ionic bond make the crystal brittle.

Thus, The strong attractive forces in ionic crystal make them rigid , hard and brittle solid.

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The true statement about the reaction is that the reaction reaches equilibrium around 1.5 seconds.

We say that a reaction is reversible if the reaction can proceed both in the forward and the reverse directions. Let us recall that it is possible for a reversible reaction to attain a status of dynamic equilibrium. The status of dynamic equilibrium is the status where the rate of the forward reaction is equal to the rate of reverse reaction.

If we look at the graph as we have it we would notice that there is such a point of dynamic equilibrium as we survey the system around 1.5 seconds.

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The true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.

Reversible reaction is defined as a reaction in which the transformation of both reactants and products into one another takes place simultaneously.

If a response may occur in both the forward and reverse directions, we say that it is reversible. Let's not forget that a reversible reaction can reach a state of dynamic equilibrium. The condition known as dynamic equilibrium occurs when the forward reaction rate and the backward reaction rate are equal.

If we were to examine the graph as it currently stands, we would see that the system reaches a point of dynamic equilibrium after 1.5 seconds of observation.

Thus, the true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.

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You should develop the TLC (thin layer chromatography) plate orthogonally (under a 90-degree angle) to the original direction of development (along its width, while the original development was along the length of the TLC plate).

This technique is called 2D TLC (two-dimensional thin layer chromatography) and is usually employed to analyze and preparatively separate very complex mixtures that cannot be separated using only one solvent system. The initial development (along the length of the TLC plate) enables crude separation into groups of compounds with similar retention factor (Rf). These groups can then be further separated using a different solvent system by developing the same TLC plate along its width.

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By using the data given in the text and the specific heat capacity of water and its density, we can calculate that the amount of heat produced by hydrocarbon combustion was 233.6 kJ.

The heat released by hydrocarbon combustion is absorbed by the calorimeter and the water in it. To calculate the amount of heat (Q) produced by the combustion, we are going to use the specific heat capacity of water (c = 4.186 J/g°C), the heat capacity of the calorimeter (q = 68.5 J/°C) and the difference in temperature (ΔT = 54.91 °C):

heat absorbed by the calorimeter = ΔT*q

heat absorbed by water = ΔT*c*m

Q = ΔT*q + ΔT*c*m

m - the mass of water

To obtain the mass of water, we are going to use the volume (V = 1000 mL) of water and its density (d = 1.00 g/mL):

d = m/V ⇒ m = d * V

m = 1.00 g/mL * 1000 mL

m = 1000 g

Now we can plug all the known values in the formula for Q:

Q = 54.91 °C * 68.5 J/°C + 54.91 °C * 4.186 J/g°C * 1000 g

Q = 233,614.595 J

Q = 233.6 kJ

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First acid solution contains 19 liters of 25% acid, second acid contains  19 liters of 45% acid, and the third contains 57 liters of 45% acid.

Let us take x as the liters of 25% acid, y as the liters of 45% acid, and z as the liters of 85% acid.

From this we get an equation:

x + y + z = 95    

0.25x + 0.45y + 0.85z = (0.65)95

By equating both the equation we have:

y + 3z = 190

y = 190 - 3z  

It is given that z = 3y

Solve the system of equations using eliminating or substituting we get:

x + y + z = 95

x + y + 3y = 95

x  + 4y = 95

x = 95- 4y

0.25( 95 - 4y ) + 0.45y + 0.85(3y) = (0.65) 95

23.75- y + 0.45y  + 2.55y = 61.75  

2y = 38

y = 19

x = 95 - 4y

  = 95 -76

   = 19

z = 3y

 = 3× 19

 = 57

Therefore the chemist needs 19 liters of 25% acid, 19 liters of 25% acid and, 57 liters of 85% acid.

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