Which is not a characteristic of a plant’s vascular tissue?

The rate constant of a reaction is 5.8 × 10−3 s−1 at 25°c, and the activation energy is 33.6 kj/mol. what is k at 75°c? enter yo

sergij07 [2.7K]

Answer:

k₂ = 4.06 x 10⁻² s⁻¹.

Explanation:

From Arrhenius law: K = Ae(-Ea/RT)

where, K is the rate constant of the reaction.

A is the Arrhenius factor.

Ea is the activation energy.

R is the general gas constant.

T is the temperature.

At different temperatures:

ln(k₂/k₁) = Ea/R [(T₂-T₁)/(T₁T₂)]

k₁ = 5.8 × 10⁻³ s⁻¹, k₂ = ??? , Ea = 33600 J/mol, R = 8.314 J/mol.K, T₁ = 298.0 K, T₂ = 348.0 K.

ln(k₂/5.8 × 10⁻³ s⁻¹) = (33600 J/mol / 8.314 J/mol.K) [(348.0 K - 298.0 K) / (298.0 K x 348.0 K)] = (4041.37) (4.82 x 10⁻⁴) = 1.9479.

Taking exponential of both sides:

(k₂/5.8 × 10⁻³ s⁻¹) = 7.014.

∴ k₂ = 4.06 x 10⁻² s⁻¹.

3 0

3 years ago

Describe how a mole ratio is correctly expressed when it is used to solve a stoichiometry problem

notka56 [123]

Basically stoichiometry is the measurement of elements, that is, the study of chemical quantities consumed or produced in a chemical reaction. When we are performing it we are using a special chemical counting unit: the mole, a unit of measurement, and one mole of a substance contains 6.022 * 10^23 particles. Now mole ratio is defined as the ratio of moles of one substance to the moles of another substance in a balanced equation. If we are looking for the mole ratio between two substances, we need to look at the balanced equations for the coefficients in front of the substances you are interested in.
This should be your guiding mantra for doing stoichiometry problems!

3 0

3 years ago

Given the standard heats of reaction

ANTONII [103]

Answer:

Explanation:

M(s) → M (g ) + 20.1 kJ --- ( 1 )

X₂ ( g ) → 2X (g ) + 327.3 kJ ---- ( 2 )

M( s) + 2 X₂(g) → M X₄ (g ) - 98.7 kJ ----- ( 3 )

( 3 ) - 2 x ( 2 ) - ( 1 )

M( s) + 2 X₂(g) - 2 X₂ ( g ) - M(s) → M X₄ (g ) - 98.7 kJ - 2 [ 2X (g ) + 327.3 kJ ] - M (g ) - 20.1 kJ

0 = M X₄ (g ) - 4 X (g ) - M (g ) - 773.4 kJ

4 X (g ) + M (g ) = M X₄ (g ) - 773.4kJ

heat of formation of M X₄ (g ) is - 773.4 kJ

Bond energy of one M - X bond = 773.4 / 4 = 193.4 kJ / mole

6 0

3 years ago

Determine the total pressure of all gases (at STP) formed when 50.0 mL of TNT (C3H5(NO3)3, , molar mass = 227.10 g/mol) reacts a

bija089 [108]

Answer:

Total pressure is 1189 atm

Explanation:

This is the reaction:

4C₃H₅(NO₃)₃ → 6N₂ + O₂ + 12CO₂ + 10H₂O

As we have the volume of TNT, we must know the density to find out the mass and then, apply molar mass to calculate mole.

TNT density = 1.654 g/mL

Density = mass / volume

1.654 g/mL = TNT mass / 50mL

1.654 g/mL . 50mL = TNT mass → 82.7 g

Mass / Molar mass = Mol → 82.7 g / 227.1 g/m = 0.364 mole

Now, we can calculate all the mole for the formed gases.

4 mole of TNT produce 6 mole N₂ ___ 1 mol O₂ __ 12 mole dioxide __ 10 mole of water

0.364 mole of TNT will produce:

- (0.364 . 6) /4 = 0.546 mole of produced nitrogen

- (0.364 . 1) /4 = 0.091 mole of produced oxygen

- (0.364 . 12) /4 = 1.092 mole of produced dioxide

- (0.364 . 10) /4 = 0.91 mole of produced vapour of water.

Total mole = 0.564 + 0.091 + 1.092 + 0.91 = 2.657 mole

Let's apply the Ideal Gases Law to find the total pressure, at STP

In STP, pressure is 1 atm for 1 mole at 273K, in a volume of 22.4 mL

But we have a volume of 50mL, and we have 2.657 total mole

Don't forget to convert 50 mL to L, cause the units for R

50 mL = 0.050L

P . 0.050L = 2.657 mol . 0.082L.atm/mol.K . 273K

P = (2.657 mol . 0.082L.atm/mol.K . 273K) / 0.050L

P = 1189 atm

3 0

3 years ago

At equilibrium, no chemical reactions take place. true or false

arsen [322]

False. At equilibrium, the rate of forward reaction is equal to the rate of backward reaction. The net concentration of both products and reactants won't change, but the reactions still take place.

6 0

3 years ago