This element has three fewer protons than oganesson

Why is the atomic mass of iron, 55.845 amu, most similar to the mass of iron-56, yet less than 56 amu? The atomic mass is the si

sattari [20]

Answer:

Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.

Explanation:

The atomic abundance of the isotopes of Iron is:

⁵⁴Fe: 5.82%

⁵⁶Fe: 91.66%

⁵⁷Fe: 2.19%

⁵⁸Fe: 0.33%

Where the Iron-56 is the most abundant isotope of Iron atom

As atomic mass is defined as the sum of the masses of the ions multiplied by its abundance, and the Iron-56 is the most abundance isotope, the atomic mass of Fe most be similar to the ⁵⁶Fe mass because is the most abundant isotope.

Right option is:

<h3>Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.</h3>

8 0

2 years ago

Express each aqueous concentration in the unit indicated.

MAXImum [283]

Answer:

a. ppb of trichloroethylene = 3 × 10⁶ ppb

b. ppm of Cl₂ = 3.8 ppm

c. Molarity = 0.0002 mol / L

d. Molarity = 0.0007 mol / L

e. For trace amount of concentrations

Explanation:

a. Given data

mass of trichloroethylene = 25 mg

Volume of water = 9.5 L

ppb of trichloroethylene = ?

Solution

As we know that

1 L = 1000 milliliters

9.5 L = 9.5 × 1000

9.5 L = 9500 millileters (ml)

we consider 25 mg = 25 millileters

ppb = (mass of solute / mass of solvent) × 1000,000,000 (1 billion)

ppb of trichloroethylene = (25 ÷ 9500) × 1000,000,000

ppb of trichloroethylene = 0.003 × 1000,000,000

ppb of trichloroethylene = 3 × 10⁶ ppb

B. Given data

Mass of Cl₂ = 38 g

volume of water = 1.00 × 10⁴ L ( 10000 L)

ppm of Cl₂ = ?

Solution

Volume of water in ml = 1 L = 1000 ml

Volume of water in ml = 10000 × 1000

Volume of water in ml = 10000000 ml

we take 38 g = 38 ml

Now we convert it to ppm

ppm = (mass of solute / mass of solvent) × 1000000 (1 million)

ppm of Cl₂ = ( 38 ÷ 10000000 ) × 1000000

ppm of Cl₂ = 0.0000038 × 1000000

ppm of Cl₂ = 3.8 ppm

C. Given data

Concentration of F⁻ ( Fluoride ion) = 2.4 ppm

Molarity = ?

Solution

As we know that 1 ppm = 0.001 g / L

2.4 ppm = 2.4 × 0.001 g/L

2.4 ppm = 0.0024 g/L

Mass of flouride ions = 0.0024 g

Now we find number of moles

moles = mass / molar mass

molar mass of F⁻ = 19 g/mol

moles of F⁻ = 0.0024 g / 19 g/mol

moles of F⁻ = 0.0002 mol

Molarity = mol of solute / liter of solution

Molarity = 0.0002 mol / 1 L

Molarity = 0.0002 mol / L

D. Given data

Concentration of NO₃⁻ ( nitrate ion) = 45 ppm

Molarity = ?

Solution

As we know that 1 ppm = 0.001 g / L

45 ppm = 45 × 0.001 g/L

45 ppm = 0.045 g/L

Mass of nitrate ions = 0.045 g

Now we find number of moles

moles = mass / molar mass

molar mass of NO₃⁻ = 62 g/mol

moles of NO₃⁻ = 0.045 g / 62 g/mol

moles of F⁻ = 0.0007 mol

Molarity = mol of solute / liter of solution

Molarity = 0.0007 mol / 1 L

Molarity = 0.0007 mol / L

E. Reason of expressing concentration in ppm and ppb

Scientist prefer ppm and ppb notations when the concentration difference of solute and solvent are very high.

As water contains contaminants is a very low amount we can say in trace amounts so scientist prefer ppm and ppb rather than molarity.

Example

Arcenic is an under ground water contaminant and its concentration of 10 μg/L is dangerous for health.

Lets change this in to molarity

mass = 10 μg

10 μg = 10 / 1000000

10 μg = 0.00001 g

now find out moles of Arcenic

moles = mass / molar mass

molar mass of arcenic = 75 g/mol

moles = mass / molar mass

moles of arcenic = 0.00001 g / 75 g/mol

moles of arcenic = 0.00000012 mol

Molarity = moles of solute / litres of solution

Molarity = 0.00000012 mol / 1 L

Molarity = 0.00000012 mol/ L

As we can see that in molarity it is a negligible amount so scientists express it in ppm and ppb

7 0

2 years ago

The combustion of ethyne, shown below unbalance, produces heat which can be used to weld metals:

Andreyy89

Answer:

3.69 g

Explanation:

Given that:

The mass m = 325 g

The change in temperature ΔT = ( 1540 - 165)° C

= 1375 ° C

Heat capacity $c_p$ = 0.490 J/g°C

The amount of heat required:

q = mcΔT

q = 325 × 0.490 × 1375

q = 218968.75 J

q = 218.97 kJ

The equation for the reaction is expressed as:

$C_2H_{2(g)} + 5O_{2(g)} \to 2CO_{2(g)} + H_2O_{(g)} \ \ \ \ \ \Delta H^o_{reaction} = -1544 \ kJ$

Then,

1 mole of the ethyne is equal to 26 g of ethyne required for 1544 kJ heat.

Thus, for 218.97 kJ, the amount of ethyne gas required will be:

$= \dfrac{26 \ g}{1544 \ kJ} \times 218.97 \ kJ$

= 3.69 g

3 0

2 years ago

Find a part of the article that describes signals that are sent within Diego’s body. Where does the signal come from, and how do

ycow [4]

Answer:

The sensory receptors send signals to Diego's brain cells. These signals are messages that help Diego figure out what to do next. As Diego thinks, more signals move from one brain cell to another.

6 0

1 year ago

If you were to perform the reaction KCl (s)→K+ (g)+ Cl−(g), would energy be absorbed or released? Lattice Energies for Some Ioni

lina2011 [118]

Answer:

Energy would be absorbed.

Explanation:

Lattice energy is defined as the energy required to break apart an ionic solid and convert its component atoms into gaseous ions. That is what you're doing in:

KCl (s) → K⁺(g) + Cl⁻(g)

The energy you require to obtain this reaction is 701 kJ/mol. As the value is positive, energy would be absorbed.

I hope it helps!

6 0

2 years ago

This element has three fewer protons than oganesson ￼

This element has three fewer protons than oganesson