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3 years ago

Why aren’t two hydrogen atoms bonded together considered a compound?

Chemistry

1 answer:

Art [367]3 years ago

4 0

Answer:

A compound by definition contains at least 2 different kinds of atoms. A Hydrogen molecule contains only one kind of atom, 2 hydrogen atoms

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Compute the molar enthalpy of combustion of glucose (C6 H12O6 ): C6 H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2 O (g) Given that com

lana66690 [7]

Answer:

The molar enthalpy of combustion of glucose is -2819.3 kJ/mol

Explanation:

Step 1: Data given

Mass of glucose = 0.305 grams

Combustion of 0.305 grams causes a raise of 6.30 °C

Calorimeter has a heat capacity of 755 J/°C

Molar mass of glucose = 180.2 g/mol

Step 2: The balanced equation

C6H12O6 (s) + 6O2 (g) → 6CO2 (g) + 6H2O (g)

Step 3:

ΔH = (m * C * ΔT + c(calorimeter) * ΔT)

with m = mass of the solutin = 0.305 grams

with C = heat capacity of water = 4.184 J/g°C

with ΔT = the change in temperature = 6.30 °C

with c(calorimeter) = 755 J/°C

ΔH = 0.305 * 4.184 *6.30 + 755 * 6.30 = 4764.5 J ( negative because it's exothermic)

Step 4: Calculate moles of glucose

Moles glucose = mass glucose / Molar mass glucose

Moles glucose = 0.305 grams / 180.2 g/mol

Moles glucose = 0.00169 moles

Step 5: Calculate molar enthalpy

Molar enthalpy = -4764.5 J / 0.00169 moles

Molar enthalpy = - 2819254.2 J/moles = -2819.3 kJ/moles

The molar enthalpy of combustion of glucose is -2819.3 kJ/mol

5 0

3 years ago

Which of these BEST describes a physical change?

OLEGan [10]

Answer:

C) a log in the campfire turns into ashes

8 0

3 years ago

Consider 2 Al + 6 HCl → 2 AlCl3 + 3 H2 , the reaction of Al with HCl to produce hydrogen gas. What is the pressure of H2 if the

Margaret [11]

Answer : The pressure of hydrogen gas is 8.96 atm.

Explanation :

The given balanced chemical reaction is:

$2Al+6HCl\rightarrow 2AlCl_3+3H_2$

From the balanced chemical reaction we conclude that,

As, 2 moles of Al react to give 3 moles of $H_2$ gas

So, 4.50 moles of Al react to give $\frac{3}{2}\times 4.50=6.75$ moles of $H_2$ gas

Now we have to calculate the moles of $H_2$ gas when percent yield is 75.4.

$\text{The moles of }H_2=75.4\% \times 6.75=\frac{75.4}{100}\times 6.75=5.09moles$

Now we have to calculate the pressure of $H_2$ gas.

Using ideal gas equation :

PV = nRT

where,

P = Pressure of hydrogen gas = ?

V = Volume of the hydrogen gas = 14.0 L

n = number of moles of hydrogen gas = 5.09 moles

R = Gas constant = $0.0821L.atm/mol.K$

T = Temperature of hydrogen gas = 300 K

Putting values in above equation, we get:

$P\times 14.0L=5.09mol\times 0.0821L.atm/mol.K\times 300K\\\\P=8.96atm$

Therefore, the pressure of hydrogen gas is 8.96 atm.

3 0

2 years ago

A substance with a ph of 9 has

Arisa [49]

Answer:

c) more OH⁻ ions than H₃O⁺ ions

Explanation:

A substance with a PH of 9 implies that it has more OH⁻ ions than H₃O⁺ ions.

Such substances are said to be an alkaline or a base.

A base is a substance the produces excess hydroxyl ion in aqueous solutions.

An acid will produce excess hydroxonium ions in a solution.

So, the pH scale is used to indicate whether a substance is an acid or base or non of them.

Acids have pH of less than 7

Bases have pH of > 7

4 0

3 years ago

When the molecules of a gas hit each other do they normally stick or bounce off

Dahasolnce [82]

Since the molecules of a gas are constantly in motion, moving and hitting other gas molecules in all directions of the enclosed container, the molecules transfer a portion of energy through the interaction of other gas particles as they hit, but then bounce off.

8 0

2 years ago

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