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2 years ago

How many micrograms of iron were in the 8.0 mL sample of Greg's blood?

1 answer:

4 0

Answer is: there is 3,36 micrograms of iron in <span>sample of Greg's blood.
</span>m(Fe) = 42 mcg(micrograms).
V(Fe) = 1 dL = 1 dL · 100 mL/1dL.
V(Fe) = 100 mL.
Make proportion: m(Fe) : 8 mL = 42 mcg : 100 mL.
100 mL · m(Fe) = 8 mL · 42 mcg.
m(Fe) = 336 mL·mcg ÷ 100 mL.
m(Fe) = 3,36 mcg.

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If a 0.4856 gram sample of khp is dissolved in sufficient water to prepare 250 ml of solution, and 25 ml of the solution require

dangina [55]

Mass of potassium hydrogen pthalate KHP is 0.4856 g, its molar mass is 204.22 g/mol, number of moles of KHP can be calculated as follows:

$n=\frac{m}{M}$

Here, m is mass and M is molar mass, putting the values,

$n=\frac{0.4856 g}{204.22 g/mol}=0.00237 mol$

This will be number of moles of NaOH at equivalent point.

Detailed calculations:

Molarity is defined as number of moles in 1 L of solution, for 250 mL of solution, molarity will be:

$M=\frac{0.00237 mol}{250 \times 10^{-3}L}=0.009511 M$

For 25 mL, apply dilution law as follows:

$M_{1}V_{1}=M_{2}V_{2}$

Putting the values,

$0.009511\times 250=M_{2}\times 25 mL$

On rearranging,

$M_{2}=\frac{0.009511\times 250}{25}=0.09511 M$

Convert molarity into number of moles,

$n=M\times V=0.09511 mol/L\times 25\times 10^{-3}L=0.00237 mol$

At equivalent point, number of moles of KHP will be equal to NaOH, thus, number of moles of NaOH will be 0.00237 mol.

Calculation for molarity:

Volume of NaOH is 18.75 mL, thus, molarity can be calculated as follows:

$M=\frac{n}{V}$

Putting the values,

$M=\frac{0.00237 mol}{18.75\times 10^{-3}L}=0.1264 M$

Therefore, molarity of NaOH is 0.1264 M

7 0

2 years ago

How much energy is required to heat 0.24 KG lutetium from 296.2K to 373.5 K? The specific heat for lutetium is 0.154 J/g-K

Olenka [21]

I’m not sure I need help with this question

6 0

2 years ago

To determine the concentration of ethanol in cognac a 5.00 mL sample of the cognac is diluted to 0.500 L. Analysis of the dilute

julia-pushkina [17]

Answer : The molar concentration of ethanol in the undiluted cognac is 8.44 M

Explanation :

Using neutralization law,

$M_1V_1=M_2V_2$

where,

$M_1$ = molar concentration of undiluted cognac = ?

$M_2$ = molar concentration of diluted cognac = 0.0844 M

$V_1$ = volume of undiluted cognac = 5.00 mL = 0.005 L

$V_2$ = volume of diluted cognac = 0.500 L

Now put all the given values in the above law, we get molar concentration of ethanol in the undiluted cognac.

$M_1\times 0.005L=0.0844M\times 0.500L$

$M_1=8.44M$

Therefore, the molar concentration of ethanol in the undiluted cognac is 8.44 M

4 0

2 years ago

For which of the following properties does sodium have a larger value than rubidium? Select all that apply.

Doss [256]

Answer:

Ionization energy

Electronegativity

Explanation:

-due to its smaller ionic radius....the electron in the outter most shell tends to expierence a stronger nuclear attraction...which makes it harder to remove the electron from the sodium atom

-Rubidium has lesser ionization energy because its (i) affected by its larger ionic radius which tends to lessen the nuclear attraction ...hence making it easier to remove the electron...(ii)and also by the screening effect done by the inner shells, which also tends to lessen the nuclear attraction.

Sodium has a higher electronegativity than rubidium;

Electronegativity is the charge density of electrons in an atom...in which its high when the atomic radius is smaller...

So hence due to the sodium atomic radius being smaller...it tends to have a higher charge density than rubidium....which then gives it a higher electronegativity value

4 0

2 years ago

On a separate sheet of paper, write the formulas for the missing components of these neutralization reactions.

Fofino [41]

The formula of the missing component are a follows

HBr + KOH ------> KBr + H2O

H2SO4 + 2NH4OH--------> (NH4)2SO4 + 2H2O

2HNO3 + Mg(OH)2 ---------> Mg(NO3)2 + 2 H2O

4 0

2 years ago

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