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3 years ago

What is Alfunim second element ? Please help !!!

1 answer:

3 0

Aluminum? It is a chemical element with the symbol Al and atomic number 13. It is a silvery-white, soft, non-magnetic and ductile metal in the boron group. By mass, aluminium is the most abundant metal in the Earth's crust and the third most abundant element

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2. Which energy source is considered a non-renewable resource?

Keith_Richards [23]

Answer:

The answer is D

Explanation:

Although natural processes continually form fossil fuels, such fuels are generally classified as non-renewable resources because they take millions of years to form and the known viable reserves are being depleted much faster than new ones are being made. ... The use of fossil fuels raises serious environmental concerns.

BRAINLIEST PLZ

8 0

3 years ago

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A compound is 40.0% c, 6.70% h, and 53.3% o by mass. assume that we have a 100.-g sample of this compound. the molecular formula

atroni [7]

When you have 100 g of compound, then based on the percentages given, there are 40.0 g C, 6.70 g H, and 53.3 g O. Convert those to moles:

C: 40.0 g / 12.0 = 3.33 moles of C
H: 6.70 g / 1.01 = 6.63 moles of H 
O: 53.3 / 16.0 = 3.33 moles of O

Dividing by the smallest (3.33), we get a C:H:O mole ratio of 1:2:1
So, The empirical formula is CH2O.
Now, That formula has a molar mass of [12.0 + 2(1.0) + 16.0] = 30.0

And we are given it's molar mass is = 240

So, no. of units of CH2O = 240 / 30 = 8

8 x CH2O = C8H16O8, and that is the molecular formula.

$C_8H_{16}O_8$

3 0

3 years ago

The normal freezing point of water is 0.00 ⁰C. What is the freezing point of a solution containing450.0 mg of ethylene glycol (M

anyanavicka [17]

Answer:

Freezing T° of solution = - 8.98°C

Explanation:

We apply Freezing point depression to solve this problem, the colligative property that has this formula:

Freezing T° of pure solvent - Freezing T° of solution = Kf . m

Kf = 1.86°C/m, this is a constant which is unique for each solvent. In this case, we are using water

m = molality (moles of solute / 1kg of solvent)

We convert the mass of solvent from g to kg

1.5 g . 1kg/1000g = 0.0015 kg

We convert the mass of solute, to moles. Firstly we make this conversion, from mg to g → 450mg . 1g/1000mg = 0.450 g

0.450 g. 1mol / 62.07g = 7.25×10⁻³ moles

Molality → 7.25×10⁻³ mol / 0.0015 kg = 4.83 m

- Freezing T° of solution = 1.86°C /m . 4.83 m - Freezing T° of pure solvent

-Freezing T° of solution = 1.86°C /m . 4.83 m - 0°C

Freezing T° of solution = - 8.98°C

8 0

3 years ago

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A closed vessel having a volume of 1 liter holds 2.5 × 1022 molecules of carbon dioxide gas. Determine the mass of CO2 present,

11111nata11111 [884]

Answer:

mass = 1.8x10⁻³ kg; number of moles = 4.1x10⁻⁵ kmol; specific volume = 0.55 m³/kg; molar specific volume = 24.4 m³/kmol

Explanation:

By the Avogadro's number, 1 mol of the matter has 6.02x10²³ molecules, thus, the number of moles (n) is the number of molecules presented divided by Avogadro's number:

n = 2.5x10²²/6.02x10²³

n = 0.041 mol

n = 4.1x10⁻⁵ kmol

The molar mass of CO₂ is 44 g/mol (12 g/mol of C + 2*16g/mol of O), and the mass is the number of moles multiplied by the molar mass:

m = 0.041 mol * 44 g/mol

m = 1.804 g

m = 1.8x10⁻³ kg

The specific volume (v) is the volume (1L = 0.001 m³) divided by the mass, and it represents how much volume is presented in each part of the mass:

v = 0.001/1.8x10⁻³

v = 0.55 m³/kg

The molar specific volume (nv) is the volume divided by the number of moles, and it represents how much volume is presented in each part of the mol:

nv = 0.001/4.1x10⁻⁵

nv = 24.4 m³/kmol

5 0

3 years ago

The combustion of Ibuprofen C13H18O2 produces water and carbon

prohojiy [21]

Answer:

277.7 g of CO2

Explanation:

Equation of reaction

C13H18O2 + 11O2 ---> 13CO2 + 9H2O

From the equation of reaction

1 mole of ibuprofen produces 13 moles of CO2

Molar mass of ibuprofen is 206g

Molar mass of CO2 is 44g

13 moles of CO2 weighs 572g

Therefore, 100g of ibuprofen will produce (100×572)/206 of CO2

= 277.7g

6 0

3 years ago