Hess’s Law can be used to determine the heat of reaction in the lab. True False

When air is heated, its density<br> A. Increases<br> B. Decreases<br> C. stays the same

soldier1979 [14.2K]

Answer:

a

Explanation:

6 0

2 years ago

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A weather balloon of known initial volume is released. The air pressures ar its initial and final altitudes are known. Why can't

Nezavi [6.7K]

Answer: you cannot find its new volume by using these known values and Boyle's law because the temperature does not remain constant.

Explanation:

Boyle's law states that the volume of a fixed amount of gas, at a constant temperature, varies inversely with the pressure.

So, it is a condition that the temperature does not change.

For the wheater ballon case, as it travels through the atmosphere, the temperature at different altitudes will be different.

So, you might use other equation of states, such as the combined law, which does deal with changes in the three variables: volume, pressure, and temperature.

The mathematical formulation of Boyle's law is:

pV = constanjt ⇒ p₁ V₁ = p₂ V₂, at constant T.

The mathematical formulation of the combined law of gases is:

pV/T = constant ⇒ p₁ V₁ / T₁ = p₂ V₂ / T₂, for a fixed amount of gas, then it might work for the weather ballon (if you know the initial and end temperatures).

5 0

3 years ago

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The atomic number of an atom is the number of ______ in the atom's nucleus. *

nasty-shy [4]

the answer would be protons

8 0

2 years ago

Determine if each statement below is True or False regarding Arrhenius and Br∅nsted-Lowry definitions for acids and bases.

Vlad1618 [11]

Answer:

All statements are true

Explanation:

Arrhenius theory:-

The Arrhenius theory was introduced introduced by Swedish scientist named Svante Arrhenius in 1887.

According to the theory, acids are the substances which dissociate in the aqueous medium to produce electrically charged atoms ( may be molecule). Out of these species furnished, one must be a proton or the hydrogen ion, $H^+$ .

Hence, statement 1 is correct.

Bronsted-Lowry base is the specie which accepts the proton form the medium. For example, Benzoate ion is the conjugate base of the benzoic acid. It is a Bronsted-Lowry base and the dissociation of benzoate ion can be shown as:-

$C_6H_5COO^-_{(aq)} + H_2O_{(l)}\rightleftharpoons C_6H_5COOH_{(aq)} + OH^-_{(aq)}$

Hence, statement 2 is correct.

Acetic acid will dissociate as:-

$CH_3COOH\rightleftharpoons CH_3COO^-+H^+$

Hence, statement 3 is also correct.

5 0

3 years ago

The combustion reaction for methane is shown below:

horrorfan [7]

Answer:

P = 14.1 atm

Explanation:

Given data:

Mass of methane = 64 g

pressure exerted by water vapors = ?

Volume of engine = 24.0 L

Temperature = 515 K

Solution:

Chemical equation:

CH₄ + 2O₂ → CO₂ + 2H₂O + energy

Number of moles of methane:

Number of moles = mass / molar mass

number of moles = 64 g/ 16 g/mol

Number of moles = 4 mol

Now we will compare the moles of water vapors and methane.

CH₄ : H₂O

1 : 2

4 : 2/1×4 = 8 mol

Pressure of water vapors:

PV = nRT

R = general gas constant = 0.0821 atm.L/mol.K

P = 8 mol × 0.0821 atm.L/mol.K× 515 K / 24.0 L

P = 338.25 atm.L/ / 24.0 L

P = 14.1 atm

4 0

2 years ago