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3 years ago

11

Doctors sometimes use computer models to track the spread of an infectious disease . How might this help them better understand

how to prevent the disease?

1 answer:

kotegsom [21]3 years ago

7 0

It could them know how it start when it started wats in the infectious disease and why

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Find the mass of 1.112 moles HF?

Alexeev081 [22]

Answer:

22.25 g

Explanation:

To find the mass, you need to convert moles to grams and get 22.25 g.

7 0

3 years ago

Determine the mass fraction of iron in its compounds:

Shkiper50 [21]

Explanation:

We have a molecule composed of 3" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: 0px; font-style: normal; font-variant: inherit; font-weight: normal; one; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">33 iron atoms, and 4" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: p; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">44 atoms of another element. We are given the following information: it has 2.36 g" role="presentation" style="box-sizing: inherit; margin: 0px; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">2.36 g2.36 g of iron for 3.26 g" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: 0px; font-style: normal; font-variant: inherit; font-weight: -wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">3.26 g3.26 g of molecule.

I want to find the molar mass of the compound, I have tried so far:

m=3.26 g=0.00326 kg" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: 0px; font-style: normal; font-variant: inherit; font-weight: normal; font-stretch: inherit; line-height: normal; font-family: inherit; font-size: 15px; vertical-align: baseline; display: inline; text-indent: 0px; text-align: center; text-transform: none; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">m=3.26 g=0.00326 kgm=3.26 g=0.00326 kg

Since it has 3" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; nt-variant: inherit; font-weight: normal; font-stretch: inherit; line-height: normal; font-family: inherit; font-size: 15px; vertical-align: baseline; display: inline; text-indent: 0px; text-align: left; text-transform: none; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">FeFe and 4" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: 0px; font-style: normal; font-variant: inherit; font-weight: normal; font-stretch: inherit; line-height: normal; ; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">44 atoms of an unknown substance, therefore:

3+4=7 atoms,1 mol=6.022⋅1023 atoms76.022⋅1023=1.16⋅10−23" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: 0px; font-style: normal; font-variant: : ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; width: 10000em !important; ; font-family: inherit; eight: none; min-width: 0px; min-height: 0px; position: relative;">0.003260.00326 by 1.16⋅10−23" role="presentation"; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">1.16⋅10−231.16⋅10−23 and I obtained 2.79429⋅1019" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: 0px; f inherit; font-size: 15px; vertical-align: baseline; display: inline; text-indent: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">2.79429⋅10

IT'S TOTAL ANSWER OF ITS AND THIS QUESTION IS IN MATHEMATION FINAL EXAM. PLEASE GIVE❤ AND MARK ME A BRAINLIST

7 0

2 years ago

When 551. mg of a certain molecular compound X are dissolved in 100 g of benzonitrile (CH,CN), the freezing point of the solutio

arsen [322]

Answer:

1.12g/mol

Explanation:

The freezing point depression of a solvent for the addition of a solute follows the equation:

ΔT = Kf*m*i

<em>Where ΔT is change in temperature (Benzonitrile freezing point: -12.82°C; Freezing point solution: 13.4°C)</em>

<em>ΔT = 13.4°C - (-12.82) = 26.22°C</em>

<em>m is molality of the solution</em>

<em>Kf is freezing point depression constant of benzonitrile (5.35°Ckgmol⁻¹)</em>

<em>And i is Van't Hoff factor (1 for all solutes in benzonitrile)</em>

Replacing:

26.22°C = 5.35°Ckgmol⁻¹*m*1

4.90mol/kg = molality of the compound X

As the mass of the solvent is 100g = 0.100kg:

4.9mol/kg * 0.100kg = 0.490moles

There are 0.490 moles of X in 551mg = 0.551g, the molar mass (Ratio of grams and moles) is:

0.551g / 0.490mol

= 1.12g/mol

<em>This result has no sense but is the result by using the freezing point of the solution = 13.4°C. Has more sense a value of -13.4°C.</em>

5 0

2 years ago

(I)how many atoms are present in 7g of lithium?

ICE Princess25 [194]

Answer :

(i) The number of atoms present in 7 g of lithium are, $6.07\times 10^{23}$

(ii) The number of atoms present in 7 g of lithium are, $1.204\times 10^{24}$

(iii) The number of moles of $F_2$ is, 1 mole

The number of moles of $CO_2$ is, 0.5 mole

The number of moles of $OH^-$ is, 1 mole

Explanation :

<u>Part (i) :</u>

First we have to calculate the moles of lithium.

$\text{Moles of }Li=\frac{\text{Mass of }Li}{\text{Molar mass of }Li}$

Molar mass of Li = 6.94 g/mole

$\text{Moles of }Li=\frac{7g}{6.94g/mol}=1.008mole$

Now we have to calculate the number of atoms present.

As, 1 mole of lithium contains $6.022\times 10^{23}$ number of atoms

So, 1.008 mole of lithium contains $1.008\times 6.022\times 10^{23}=6.07\times 10^{23}$ number of atoms

Thus, the number of atoms present in 7 g of lithium are, $6.07\times 10^{23}$

<u>Part (ii) :</u>

First we have to calculate the moles of carbon.

$\text{Moles of }C=\frac{\text{Mass of }C}{\text{Molar mass of }C}$

Molar mass of C = 12 g/mole

$\text{Moles of }C=\frac{24g}{12g/mol}=2mole$

Now we have to calculate the number of atoms present.

As, 1 mole of carbon contains $6.022\times 10^{23}$ number of atoms

So, 2 mole of carbon contains $2\times 6.022\times 10^{23}=1.204\times 10^{24}$ number of atoms

Thus, the number of atoms present in 7 g of lithium are, $1.204\times 10^{24}$

<u>Part (iii) :</u>

<u>To calculate the moles of </u> $F_2$ <u> :</u>

$\text{Moles of }F_2=\frac{\text{Mass of }F_2}{\text{Molar mass of }F_2}$

Molar mass of $F_2$ = 38 g/mole

$\text{Moles of }F_2=\frac{19g}{19g/mol}=1mole$

Thus, the number of moles of $F_2$ is, 1 mole

<u>To calculate the moles of </u> $CO_2$ <u> :</u>

$\text{Moles of }CO_2=\frac{\text{Mass of }CO_2}{\text{Molar mass of }CO_2}$

Molar mass of $CO_2$ = 44 g/mole

$\text{Moles of }CO_2=\frac{22g}{44g/mol}=0.5mole$

Thus, the number of moles of $CO_2$ is, 0.5 mole

<u>To calculate the moles of </u> $OH^-$ <u> ions :</u>

$\text{Moles of }OH^-=\frac{\text{Mass of }OH^-}{\text{Molar mass of }OH^-}$

Molar mass of $OH^-$ = 17 g/mole

$\text{Moles of }OH^-=\frac{17g}{17g/mol}=1mole$

Thus, the number of moles of $OH^-$ is, 1 mole

4 0

3 years ago

Calcium hydroxide, Ca(OH)2, is an ionic compound with a solubility product constant, Ksp, of 6.5×10–6. Calculate the solubility

kari74 [83]

Answer: The solubility of this compound in pure water is 0.012 M

Explanation:

Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as $K_{sp}$

The equation for the ionization of the is given as:

$Ca(OH)_2\rightarrow Ca^{2+}+2OH^-$

By stoichiometry of the reaction:

1 mole of $Ca(OH)_2$ gives 1 mole of $Ca^{2+}$ and 2 mole of $OH^-$

When the solubility of $Ca(OH)_2$ is S moles/liter, then the solubility of $Ca^{2+}$ will be S moles\liter and solubility of $OH^-$ will be 2S moles/liter.

$K_{sp}=[Ca^{2+}][OH^{-}]^2$

$6.5\times 10^{-6}=[S][2S]^2$

$S=0.012M$

Thus solubility of this compound in pure water is 0.012 M

5 0

3 years ago