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3 years ago

Why does metal need to be extracted from an ore before it can be used?

1 answer:

7 0

Metal ore has other elements in it as well. Also sediment and stone might cover the ore. We don't want to have a phone with sediment on it do we? thus these few reasons are why.

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1. Ibuprofen (C13H18O2) is the active ingredient in many nonprescription pain relievers. Each tablet contains 200 mg of ibuprofe

Dmitry_Shevchenko [17]

Answer :

The molar mass of ibuprofen is, 206.29 g/mole.

The number of moles of ibuprofen in a single tablet is, 0.000969 moles

The number of moles of ibuprofen in four doses is, 0.007752 moles

Solution : Given,

Molar mass of carbon = 12.01 g/mole

Molar mass of hydrogen = 1.01 g/mole

Molar mass of oxygen = 15.99 g/mole

1) Now we have to calculate the molar mass of ibuprofen.

Molar mass of ibuprofen, $C_{13}H_{18}O_2$ = $(13\times 12.01)+(18\times 1.01)+(2\times 15.99)=206.29g/mole$

The molar mass of ibuprofen = 206.29 g/mole

2) Now we have to calculate the moles of ibuprofen.

Formula used : $Moles=\frac{Mass}{\text{ Molar mass}}$

Given : Mass of ibuprofen = 200 mg = 0.2 g (1 mg = 1000 g)

$\text{ Moles of ibuprofen}=\frac{\text{ Mass of ibuprofen}}{\text{ Molar mass of ibuprofen}}=\frac{0.2g}{206.29g/mole}=0.000969moles$

The moles of ibuprofen = 0.000969 moles

3) Now we have to calculate the number of moles of ibuprofen for four doses.

Number of tablets in one dose = 2

Total number of tablets in 4 doses = 4 × 2 = 8

Number of moles of ibuprofen in 8 tablets =

$\text{ Number of moles of ibuprofen in 1 tablet}\times \text{ Total number of tablets}=0.000969\times 8=0.007752moles$

6 0

3 years ago

Read 2 more answers

Different isotopes of the same element must have a different

slega [8]

Answer:

they must have same atomic number and different atomic mass

6 0

3 years ago

Based on the "Heating Curve for Wax," what is the boiling point for wax?

alukav5142 [94]

Looks like 340°C to me

4 0

3 years ago

Read 2 more answers

The half-life of radium-226 is 1590 years. (a) A sample of radium-226 has a mass of 50 mg. Find a formula for the mass of the sa

Maksim231197 [3]

Answer:

Explanation:

a )

m = m₀ $e^{-\lambda t$

m is mass after time t . original mass is m₀ , λ is disintegration constant

λ = .693 / half life

= .693 / 1590

= .0004358

m = m₀ $e^{- 0.0004358 t}$

b )

m = 50 x $e^{-.0004358\times 500}$

= 40.21 mg .

c )

40 = 50 $e^{-.0004358t$

.8 = $e^{-.0004358t$

$e^{.0004358t$ = 1.25

.0004358 t = .22314

t = 512 years .

4 0

3 years ago

What do atomic-scale models show you that your observations of properties cannot?

Zigmanuir [339]

The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element.

4 0

3 years ago