How many molecules are present in 187 grams of XeF4

Answer:

B. Protons and Electrons

Explanation:

Protons have a positive charge and electrons have a negative charge. When an element contains the same number of both of those particles the charges will cancel out leaving the atom with a neutral charge, as neutrons already have a neutral charge.

Answer:

Q8) True

Q9) First ionization energy

Q10) Metal oxides

Explanation:

A common property of group one elements (alkali metals) is their combination with water to form basic solutions. E.g 2K(s)+2H2O(l)→2KOH(aq)+H2​(g).

The distance of the outermost electron in the atom from the nucleus is inversely related to the first ionization energy. As the distance between the outermost electron and the nucleus in group 17 elements gets larger, the corresponding first ionization energies of elements in the group gets smaller.

Group 1 elements can combine with oxygen to give metal oxides. E.g  4K + O2 --> 2 K2O

So to answer this question first let's decribe precision vs accuracy.

Precision in this case means exact and accurate; in this scenario all of the dots next to each other mean that it is highly precise.

Whereas Accuracy means aiming for the middle of the circle in this case. Thus   the accuracy is low, but the precision is high.

TLDR: It is highly precise but not accurate.

Look up "Accuracy vs. Precision: What’s the Difference?" for a better detailed example and solution.

Answer:

The percent composition of a component in a compound is the percent of the total mass of the compound that is due to that component. To calculate the percent composition of a component in a compound: Find the molar mass of the compound by adding up the masses of each atom.

Answer:

Superscript 6 Subscript 2 Baseline Upper H e right arrow Superscript 6 Subscript 3 Baseline Upper L i + Superscript 0 Subscript negative 1 Baseline e

Explanation:

Helium decays by beta emission, in beta emission, the mass number of the parent and daughter nuclei are the same but the atomic number of the daughter nucleus increases by one hence it is found one place to the right of its parent in the periodic table.

Having said this, the decay of Helium to lithium may be written as follows;

6/2He -> 6/3Li + 0/-1e

Answer:

C

Explanation:

Edge 2020

a) A1₂S₃ + 6H₂O → 3H₂S + 2Al(OH)₃ +3H₂S

b) 5.72grams of aluminum hydroxide.

It demonstrates that each molecule of aluminum sulfide yields two molecules of aluminum hydroxide, or two molecules of Al(OH)3 for every molecule of aluminum sulfide.

Al(OH)3 has a molecular weight of 78 while Al2S3 has a molecular weight of 150. Starting with 5.5 grams of aluminum sulfide, we can set up the ratio by dividing it by 150 to get x/156.

5.5/ 150 = x/156

where x represents the quantity of Al(OH)3 that was created.

Since two moles of Al(OH)3 are created for every mole of Al2S3 that reacts, we utilize 156, which is twice as much as 78. As a result, we arrive at x = (5.5)(156)/150 = 5.72 gm. To the nearest decigram, we obtain 5.72grams of aluminum hydroxide.

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Answer:

5 valence electrons

Explanation:

Answer:

5 electrons

Explanation:

Because atomic number of Nitrogen is 7 total 7 electrons are present 2 in first shell and 5 in valence shell

So these 5 electrons are known as valence electrons

Answer:

a. 2.6 x 102 ms

Explanation:

Initial mass [Ao] = 99 g

Final mass [A] = 0.50 g

Half life (t1/2) = 35 ms

Time ( t ) = ?

]The integrated rate law for first order reactions is given as;

To obtain k, we look at the expression for the half life of a first order reaction;

t1/2 = 0.693 / k

k = 0.693 / 35 = 0.0198 ms-1

ln[A] = ln[Ao] - kt

kt = ln[Ao] - ln[A]

t =   ( ln[Ao] - ln[A]  )  / k

t =  ( ln(99) - ln (0.50)  )  /  0.0198

t = 5.288 / 0.0198

t = 267.07 ms

correct option is;

a. 2.6 x 102 ms

Answer:

D. fusing 5 kg of hydrogen.

Explanation:

Answer:

Elemental gold to have a Face-centered cubic structure.

Explanation:

From the information given:

Radius of gold = 144 pm

Its density = 19.32 g/cm³

Assuming the structure is a face-centered cubic structure, we can determine the density of the crystal by using the following:

[tex]a = \sqrt{8} r[/tex]

[tex]a = \sqrt{8} \times 144 pm[/tex]

a = 407 pm

In a unit cell, Volume (V) = a³

V = (407 pm)³

V = 6.74 × 10⁷ pm³

V = 6.74 × 10⁻²³ cm³

Recall that:

Net no. of an atom in an FCC unit cell = 4

Thus;

[tex]density = \dfrac{mass}{volume}[/tex]

[tex]density = \dfrac{ 4 \ atm ( 196.97 \ g/mol) (\dfrac{1 \ mol }{6.022 \times 10^{23} \ atoms})}{6.74 \times 10^{-23} \ cm^3}[/tex]

density d = 19.41 g/cm³

Similarly; For a  body-centered cubic structure

[tex]r = \dfrac{\sqrt{3}}{4}a[/tex]

where;

r = 144

[tex]144 = \dfrac{\sqrt{3}}{4}a[/tex]

[tex]a = \dfrac{144 \times 4}{\sqrt{3}}[/tex]

a = 332.56 pm

In a unit cell, Volume V = a³

V = (332.56 pm)³

V = 3.68 × 10⁷ pm³

V  3.68 × 10⁻²³   cm³

Recall that:

Net no. of atoms in BCC cell = 2

∴

[tex]density = \dfrac{mass}{volume}[/tex]

[tex]density = \dfrac{ 2 \ atm ( 196.97 \ g/mol) (\dfrac{1 \ mol }{6.022 \times 10^{23} \ atoms})}{3.68 \times 10^{-23} \ cm^3}[/tex]

density =17.78 g/cm³

From the two calculate densities, we will realize that the density in the face-centered cubic structure is closer to the given density.

This makes the elemental gold to have a Face-centered cubic structure.

Answer:

CO2 < CH3Br < CH3OH < RbF

Explanation:

The boiling point of the compounds can be determined in terms of the strength of the intermolecular forces present in each compound.

Intermolecular forces are weak forces joining non-polar and polar molecules together. We have London dispersion forces, dipole-dipole forces of attraction, and hydrogen bonding.

London dispersion forces are weak attractions found between non-polar and polar symmetrical molecules. They are the weakest of all the electrical forces and they act between atoms and molecules e.g CO2

The dipole-dipole attractions are forces of attraction existing between polar unsymmetrical molecules. The dipole-dipole force of attractions is much stronger than London dispersion forces but weaker than Hydrogen bonding. e.g  CH3Br

Hydrogen bonding is a special dipole-dipole attraction between polar molecules in which a hydrogen atom is directly joined to a highly electronegative atom (e.g. oxygen, nitrogen, or fluorine). Here, the bond in CH3OH is a hydrogen bond.

Ionic bonding is a bond that is formed between two kinds of atoms having a large electronegative difference such as in RbF,

Thus, in increasing order of boiling point;

CO2 < CH3Br < CH3OH < RbF

Viscosity is an crucial factor in food preparation and serving. Cooking oils' viscosity may or may not change as they heat, but many become much more viscous as they cool.

Viscosity refers to the resistance of a fluid (liquid or gaseous state) to a shape shift or mobility of neighboring portions relative to one another. Viscosity indicates flow resistance.

Gathering viscosity data on a material allows manufacturers to predict how the material will start behaving in the real world. For example, if toothpaste does not have the correct viscosity, it may be difficult or impossible to pump out of the tube.

Thus, it is important to have the knowledge of viscosity.

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It would make the planet's tilt harder to change, which would mean a more stable climate, which “just means maybe ice ages wouldn't happen as often,” he told me.

The average weather throughout a region's long term, usually 30 years, is called the climate. More precisely, it is the mean and variability of meteorological variables over a period of time that can range from a few months to many millions of years. Temperature, humidity, air pressure, wind speed, and precipitation are a few of the meteorological parameters that are frequently observed.

Climate, in a larger sense, refers to the interactions between the atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere as well as their status as parts of the climate system. Latitude/longitude, topography, altitude, land use, and the presence of surrounding water bodies and their currents all have an impact on a place's climate.

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when nitric oxide reacts with oxygen GIVES Nitrogen dioxide.

NO(g)+ [tex]0_2[/tex]=2N[tex]O_2[/tex] is the balanced reaction

here, from the above reaction, we have found that

1 mole of NO and 2 mole of [tex]0_2[/tex] gives 2 mole of N[tex]O_2[/tex]

from the mole concentration, we can conclude that oxygen is limiting reactant.

A limiting reactant is an active ingredient in a reaction that is totally consumed by its conclusion. The limiting reactant determines how much product is produced in a chemical process.

In a chemical reaction, the reactants react in a stoichiometric sequence to produce the products. The limiting reactant is the one that is present in lower stoichiometric amounts. The amount of the product created depends on how much of the limiting reactant is used up in the reaction. Excess reactants are the additional reactants in the reaction besides the limiting reactants.

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Answer:

Each principal energy level has one sublevel containing one orbital, an s orbital, that can contain a maximum of two electrons.

Explanation:

Answer:

2n

Explanation:

Mass of Zirconium (Zr) in 0.040 moles : 3.6 g

The mole is the number of particles(molecules, atoms, ions) contained in a substance  

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

Moles can also be determined from the amount of substance mass and its molar mass

[tex]\tt n(mol)=\dfrac{m(mass)}{MW(molecular~weight)}[/tex]

moles of Zirconium : 0.04

mass of Zirconium (MW=91,224 g/mol) :

[tex]\tt mass=mol\times MW\\\\mass=0.04\times 91,224\\\\mass=3.6~g[/tex]

The mass in grams of 255mL of mercury if it has a density of 13.34g/mL is 3401.7g.

The mass of a substance can be calculated by multiplying the volume of the substance by its density as follows:

Mass = density × volume

According to this question, 255mL of mercury has a density of 13.34g/mL. The mass is calculated as follows:

Mass = 13.34g/mL × 255mL

Mass = 3401.7g

Therefore, the mass in grams of 255mL of mercury if it has a density of 13.34g/mL is 3401.7g.

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Answer:

Well, there are a few reasons to be curious..

Being curious can: Keep your mind active instead of passive.

Keeps your mind observant on new ideas.

It also opens up new possibilities and keeps you creative.

You can have more excitement and mysteries in life!

Explanation:

Answer: I think you need to be curious because that is how we explore things. Many people find things interesting and if you don't inspect basically you will never learn to question right or wrong things.

Explanation:

Answer:

what are the options? I'll edit my answer to the correct one once you inform me lol

Answer:

b

Explanation:

Answer:

hot dog

Explanation:

Answer:snow i think

Explanation:

Answer:

snow

Explanation:

Answer:

Answer:

the answer is neurtons

Explanation:

Answer:

HCl

Explanation:

Volume = 25L

Temperature = 25.0 oC + 273 = 298 K (Converting to kelvin units)

Pressure = 1.2 atm

Mass of gas = 44.7g

Formular of gas = HX

To solve this, we have to know the identity of X. One qay to do that is by obtaining the molecular mass of the compound.

To get the molar mass, we need the number of mole.

Using the ideal gas equation;

PV = nRT

where R = gas constant = 0.082 057 L atm K−1  mol−1

n = PV / RT

n = 1.2 * 25  / 0.082 057 * 298

n = 30  /  24.45

n = 1.227 mol

The relationship between number of moles and molar mass is given as;

Nummber f moles = mass  / molar mass

Molar mass = mass  / Number of moles

Molar mass = 44.7 / 1.227

Molar mass =  36.43 g/mol

Molar mass of gas X = Molar mass of H + Molar mass of X

36.43 = 1 + X

X = 36.43 - 1 = 35.43

Chlorine is the only element with molar mass approximate to 35.43

Hence X = Cl

The chemical formular = HCl

Answer:

4

Explanation:

The Atomic number of beryllium is 4, which means that it has 4 protons.

The amount that the child should receive is 10 mg.

The term dose refers to the amount of drugs that a person should take. The dose of the drug  is in proportion to the magnitude of the illness. The more severe the symptoms, the higher the dosage.

Since the child is to receive only 20% of the adult dose, we have;

20/100 * 50.0 mg

= 10 mg

The amount that the child should receive is 10 mg.

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Answer:

East

Explanation:

Given Newton's third law of motion; "Action and reaction are equal and opposite", when a student jumps off a sled toward the west after it stops at the bottom of an icy hill, the sled will move in the East direction.

This is because, the force exerted on the sled is a reaction force and is opposite in direction to the force that thrusts the boy westward though equal in magnitude with the former.

This question is incomplete, the complete question is;

A 1.00 g sample of NH4NO3 is decomposedin a bomb calorimeter. The temperature increases by 6.12°C. What is the molar heat of decomposition for ammonium nitrate?

Molar mass, NH4NO3 80.0 g/mol

Calorimeter Constant   1.23 kJ/°C

Answer:

the molar heat of decomposition for ammonium nitrate is - 602.4 kJ/mol

Explanation:

Given that;

change in temperature ΔT = 6.12 °C

Calorimeter Constant C = 1.23 kJ/°C

Molar mass, NH4NO3 = 80.0 g/mol

we know that;

Heat gained by the calorimeter (Q1) = Heat lost by the decomposition of NH4NO3 (Q2)

Q1 = C × ΔT

Q1 = (1.23 kJ/K) × (6.12 K) = 7.53 kJ

Q value we get becomes negative since we are talking about reaction and not calorimeter

hence

Q1 = - 7.53 kJ

now

1 g NH4NO3 decomposed, - 7.53 kJ of heat is released

so if 80 g which is 1 mol NH4NO3 decompose, the heat will be;

(80 g/mol x -7.53 kJ) / 1 g = - 602.4 kJ/mol

Therefore the molar heat of decomposition for ammonium nitrate is - 602.4 kJ/mol

Answer:

ATP is a stored form of energy

Explanation:

it is the main source of this