please help!!!! chemistry question

Explaining the concept:

Molar mass of an element is the mass of 6.022*10²³ atoms of that element

a group of 6.022*10²³ atoms or molecules is called 1 mole of that specific element or compound

this number is so large that even though atoms are very small, 6.022*10²³ of them weigh several grams depending on the element the atom belongs to.

Atoms with a larger atomic number have more protons and neutrons than atoms with small atomic number; more protons and neutrons means that they have more matter and hence, more mass

that's why elements with a large atomic number are heavier

for example:

the molar mass (mass of 1 mole or 6.022*10²³ atoms) of hydrogen is approximately '1' grams per mole

whereas,

the molar mass of Carbon (C), (which has only 5 electrons more than hydrogen) is 12 grams per mole

Solving the question:

Finding the number of Moles:

We are given 5.4 grams of Boron (B)

the molar mass of boron is 11 grams per mole

To calculate the number of moles of an element, we divide the given mass by the molar mass

Number of moles = Given mass / Molar mass

Number of moles = 5.4 / 11

Number of moles = 0.5 (approx)

Finding the number of Atoms:

Now that we have the number of moles, we can easily find the number of atoms by dividing it by 6.022*10²³ (since a group of 6.022*10²³ atoms is 1 mole)

Number of Atoms = Number of moles * 6.022*10²³

Number of atoms = 0.5 * 6.022*10²³

Number of atoms = 3.011 * 10²³

Answer:

7.133 g/cm^3

Explanation:

Density = mass ÷ volume

Given,

mass = 14.98 g

Volume = 2.10 ml = 2.10cm^3 [because 1 ml= 1cm^3]

density = 14.98÷ 2.10

density = 7.133 g/cm^3

Answer:

[tex]\boxed {\tt d\approx7.13 \ g/mL}[/tex]

Explanation:

The density of an object can be found by dividing the mass by the volume.

[tex]d=\frac{m}{v}[/tex]

The mass of the cylinder is 14.98 grams.

The volume of the cylinder is 2.10 milliliters.

[tex]m=14.98 \ g\\v= 2.10 \ mL[/tex]

Substitute the values into the formula.

[tex]d=\frac{14.98 \ g}{2.10 \ mL}[/tex]

Divide.

[tex]d=7.13333333 \ g/mL[/tex]

Round to the nearest hundredth. The 3 in the thousandth place tells us to leave the 3 in the hundredth place.

[tex]d\approx 7.13 \ g/mL[/tex]

The density of the cylinder is about 7.13 grams per milliliter.

Answer:

2.408 x 10^14

Explanation:

Answer: Oxygen or carbon I’ll say oxygen

Explanation:

Explanation:

A polyatomic ion refers to an ion that contains more than one atom.

Potassium Bicarbonate contains the Potassium ion and bicarbonate ion.

The formula is given as; KHCO₃

Aluminium Phosphate contains the Aluminium ion and Phosphate ion.

The formula is given as; AlPO4

Copper(II)hydroxide contains copper ion and hydroxide ion.

The formula is given as; Cu(OH)₂

Answer:

597K

Explanation:

Given parameters:

Initial pressure = 1.2atm

Initial temperature = 125°C = 125 + 273 = 398K

Initial volume = 1.00L

Final pressure = 1.80atm

Final volume  = 1.00L

Unknown:

Final temperature = ?

Solution:

To solve this problem, we must understand that at constant volume, the pressure of a given mass of gas varies directly with the absolute temperature.

Mathematically;

              [tex]\frac{P_{1} }{T_{1} }[/tex] = [tex]\frac{P_{2} }{T_{2} }[/tex]

where P and T are the pressures

           1 and 2 are the initial and final states

Now insert the parameters and solve;

         [tex]\frac{1.2}{398}[/tex]   = [tex]\frac{1.8}{T_{2} }[/tex]

         T₂ x 1.2 = 398 x 1.8

         T₂ = 597K

Answer:

intestines?

Explanation:

apparently my answer needs to be 20 words long so I'ma write all this so i can answer

Answer:

Explanation:

Dmitri Mendeleev was a Russian scientist that proposed the first periodic table of elements. Elements in his periodic table were arranged according to there relative atomic mass; however cobalt (Co) with an atomic mass of 58.93 was placed before nickel (Ni) with an atomic mass of 58.69 which was an anomaly as according to his law, nickel should come before cobalt since nickel has a lesser mass compared to cobalt.

Answer:

question no 4 answer is electrons

Answer:

Limiting Reactant is going to be NaOH or HCl with given lowest moles. Excess will be the ones with more.

Explanation:

Excess and Limiting reactants are based on the amount you could make in an ideal reaction. M (molarity) is the concentration of the given solutions where moles in the amount (the important part) you have of each. If you only have 0.0100 mol NaOH while you have 0.0400 mol HCl the most a reaction has the potential to use is that 0.0100 mol NaOH, thus making it the limiting reactant as it is limiting the possible amount made. The excess here is 0.0300 mol HCl.

Answer:

the answer is in the screenshot

Explanation:

hope this helps

Moles of any substance is given by the molar mass and the mass. The volume of EDTA required to titrate is 3.16 mL and the volume of zinc required to titrate is 22.8 mL.

Molarity is the property of the solution that gives the concentration of the solute present in the solution.

Given,

Mass of cobalt sulfate = 1.697 gm

The molar mass of cobalt sulfate = 155 g/mol

In the first part, the volume of the aliquot is 25 mL and the molarity is 0.08640 M.

The reaction is shown as:

Co²⁺ + H₄Y → CoH₂Y + 2H⁺

Moles of cobalt: n = 0.001694 ÷ 155 = 0.0000109 moles

In 25 ml aliquot moles of cobalt are, 0.000273 moles.

The volume of EDTA solution is calculated as:

V = moles ÷ Molarity

= 0.000273 mole ÷ 0.0864 mol/ L

= 3.16 mL

Hence, 3.16 mL of EDTA is required.

For the second part, moles of EDTA are calculated as:

n = 0.008640 × 0.050 = 4.32 ×10⁻⁴

In a 25 mL, sample moles of EDTA are 2.16 × 10⁻⁴ moles.

Excess moles of EDTA in the solution:

0.000432 - 0.000216 = 0.000216 moles

The volume of EDTA is calculated as:

V = 0.000216 ÷ 0.009450

= 0.0228 L

Hence, 22.8 mL of zinc is required.

Learn more about molarity here:

https://brainly.com/question/22714469

#SPJ2

Answer:

5.6 x 10¹⁴m

Explanation:

Given parameters:

Wavelength  = 5.4 x 10⁻⁷m

Unknown:

Frequency of the electromagnetic radiation = ?

Solution:

The speed of all electromagnetic radiation is given as 3.0 x 10⁸m/s

  So;

         Speed = frequency x wavelength

  Wavelength = [tex]\frac{speed}{frequency}[/tex]

 Insert the parameters and solve;

   Wavelength = [tex]\frac{3 x 10^{8} }{5.4 x 10^{-7} }[/tex]  

  Wavelength  = [tex]\frac{3}{5.4}[/tex]  x 10⁸⁻⁽⁻⁷⁾

  Wavelength  = 5.6 x 10⁻¹ x 10¹⁵

   Wavelength  = 5.6 x 10¹⁴m

Answer:

homolytic cleavage of a covalent bond.

Explanation:

Homolytic cleavage: In chemistry, the term "homolytic cleavage" is described as a process that involves breaking of a particular covalent bond in a way that every fragment tends to get "one" shared electrons and it often produces or gives rise to free radicals. It is also referred to as "homolysis" or "homolytic bond cleavage".

In the question above, the given statement represents "homolytic cleavage of a covalent bond".

Answer:

The most basic solution is A

Explanation:

In order to solve the problem, we can compare the pH of the solutions. The most basic solution is the one with the highest pH.

A. [H⁺] = 1 × 10⁻¹⁰ M

pH = - log [H⁺] = - log (1 × 10⁻¹⁰) = 10

B. pOH = 6.7

pH = 14 - pOH = 14 - 6.7 = 7.3

C. [OH⁻] = 7 × 10⁻⁵ M

pOH = - log [OH⁻] = -log (7 × 10⁻⁵) = 4.15

pH = 14 - pOH = 14 - 4.15 = 9.8

D. pH = 4.2

According to this, solution A has the highest pH (pH=10), thus this is the most basic solution.

Answer:

O Winds spiraling dowrward and away from the center of a storm.

Explanation:

this is correct

Answer:

ΔH=9.2 KJ

Explanation:

2NO₂→N₂O₄  ΔH=-57 KJ/mol

N₂ + O₂→2NO ΔH=180.6 KJ/mol

2NO + O₂→2NO₂ ΔH= -114.4 (notice this was reversed and sign changed

_____________________________________________

N₂+2O₂→N₂O₄ ΔH= 9.2 KJ

By reversing the third equation, we can get the O₂ on the left side or the (reactant side) so that we can get a total of 2O₂ in the final equation on the bottom. Cross out 2NO₂ on the first equation on the reactant side and 2NO₂ in equation 2 on the product side. You also want to cross out 2NO in the third equation on both the reactant and product side. This leaves the same above the line as below the line.

Since you reverse equation 3, the change in enthalpy will change sign so you input -57, 180.6 and -114.4 to get 9.2 KJ

Hope that helps.

Answer:

Negative

Explanation:

Because i learned it in 5th grade

Answer:

negative

Explanation:

When you are missing an electron or two, you have a positive charge. When you have an extra electron or two, you have a negative charge.

Answer:

Adrenal and Hypothalamus!

Explanation:

Hope this helps!

Answer:

A man is walking in the park at night when he sees a shadow suddenly dart across his path. Which glands will be responsible for controlling his “fight or flight” reaction? Check all that apply.

Adrenal and Hypothalamus

A woman goes to the doctor for blood tests because she has not been feeling well. Tests show that the sugar levels in her blood are too high. In which gland does she most likely have a problem?

Pancreas

Explanation:

Answer:

231.59 mL

Explanation:

From the question given above, the following data were obtained:

Initial volume (V₁) = 125 mL

Initial temperature (T₁) = 300 k

Initial pressure (P₁) = 2.39 atm

Final temperature (T₂) = 500 k

Final pressure (P₂) = 2.15 atm

Final volume (V₂) =..?

The new volume of the gas (V₂) can be obtained by using the combined gas equation as shown below:

P₁V₁ /T₁ = P₂V₂ /T₂

2.39 × 125 /300 = 2.15 × V₂ /500

Cross multiply

300 × 2.15 × V₂ = 2.39 × 125 × 500

645 × V₂ = 149375

Divide both side by 645

V₂ = 149375/645

V₂ = 231.59 mL

Therefore, the new volume of the gas is 231.59 mL

Answer:

A. Mo

Explanation:

The given electron configuration: 1s22s22p63s23p64s23d104p65s24d4 shows 42 electrons and Molybdenum has atomic number 42.

But the correct electronic configuration of molybdenum is  [Kr]4d5 5s1, and not [Kr]5s24d4 which is based on the diagonal rule.

The diagonal rule states that a half full 5s subshell and half-full 4d subshell are more stable than a full 5s subshell and 4d filled with four electrons.

Hence, the correct element is "A. Mo".

Answer:

Group 8A (or VIIIA) of the periodic table are the noble gases or inert gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The name comes from the fact that these elements are virtually unreactive towards other elements or compounds.

Explanation:

its XE

Answer:

so if an atom needs and electron it will form a bond with another so it will balance out.

Explanation:

Answer:

62.174

Explanation:

volume = mass/density

143/2.3 = 62.174