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notsponge [240]
3 years ago
6

Which is the best pure substance gold or air?

Chemistry
2 answers:
Elena L [17]3 years ago
7 0
Gold is the best pure substance. The answer is gold
ehidna [41]3 years ago
7 0
It is gold!!!!!!!!!!!!!!!!!!
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How can you tell from the name the types of bonds present in a hydrocarbon?
Darya [45]

Answer:

Alkane

Alkene

Alkyne

Explanation:

Alkane=1 bond (Saturated hydrocarbon)

Alkene= 2 bonds (Unsaturated hydrocarbon)

Alkyne= triple bonds (Unsaturated hydrocarbon)

Formula of Alkane = CnH2n+2

Formula of Alkene = CnH2n

Formula of Alkyne = CnH2n-2

7 0
3 years ago
Read the given equation. 2Na + 2H2O ? 2NaOH + H2 During a laboratory experiment, a certain quantity of sodium metal reacted with
emmasim [6.3K]

Answer:

The number of moles of Na metal that used initially = 0.70 mol.

The quantity of Na metal used initially to produce 7.80 of H₂ gas = 16.02 g.

Explanation:

  • It is a stichiometry problem.

<em>2Na + 2H₂O → 2NaOH + H₂,</em>

  • The balanced equation shows that <em>2.0 moles of Na metal </em>react with 2.0 moles of water to produce 2.0 moles of NaOH and <em>1.0 mole of H₂</em>,
  • Firstly, we need to convert the volume of H₂ (7.80 L) produced to no. of moles (n) using the ideal gas law: <em>PV = nRT</em>,

where, P is the pressure of the gas in atm<em> (P at STP = 1.0 atm)</em>,

V is the volume of the gas in L <em>(V = 7.80 L)</em>,

n is the number of moles in mole,

R is the general gas constant<em> (R = 0.082 L.atm/mol)</em>,

T is the temperature of the gas in K <em>(T at STP = 0.0 °C + 273 = 273.0 K)</em>.

∴ The number of moles of H₂ gas (n) = PV / RT = [(1.0 atm)(7.80 L)] / [(0.082 L.atm/mol.K)(273.0 K)] = 0.35 mol.

<em>Using cross multiplication:</em>

2.0 moles of Na will produce → 1.0 mole of H₂, from the stichiometrey.

??? moles of Na will produce → 0.35 mole of H₂.

∴ The number of moles of Na metal that used initially = (2.0 mol)(0.35 mol) / (1.0 mol) = 0.70 mol.

Now, we can get the quantity of Na metal using the relation:

∴ mass = n x molar mass = (0.70 mol)(22.989 g/mol) = 16.02 g.

6 0
3 years ago
Last week you reacted magnesium with a hydrochloric acid aqueous solution and hydrogen gas was produced. Let's say that you coll
miv72 [106K]

Answer:

69.8 kilo Pasacl is the pressure of the hydrogen gas.

Explanation:

Mg+2HCl\rightarrow MgCl_2+H_2

Pressure at which hydrogen gas collected = p = 101.2 kilo Pascals

Vapor pressure water = p^o = 31.4 kilo Pascals

The pressure of hydrogen gas = P

The pressure at which gas was collected was sum of vapor pressure of water and hydrogen gas.

p=P+p^o

P =p-p^o=101.2 kPa-31.4 kPa=69.8 kPa

69.8 kilo Pasacl is the pressure of the hydrogen gas.

3 0
3 years ago
____ is the amount of matter in an object. Question 1 options: Matter Gravitational Pull Mass Weight
saw5 [17]

Answer:

mass or matter

Explanation:

i think

3 0
3 years ago
These are all chemistry questions please help
SpyIntel [72]

Answer:

cant read the questions...

Explanation:

4 0
3 years ago
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