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2 years ago

Is anyone good at 10th grade chemistry ? If so can you help me please

Chemistry

1 answer:

Harrizon [31]2 years ago

5 0

Answer:

221.7 K

Explanation:

As, PV = nRT

Hence,

6.5 (14) = 5(0.0821)T

91 = 0.4105 T

91 ÷ 0.4105 = T

221.7 = T

Hence the required temperature is 221.7 K (Ans)

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What is the coefficient for CO2?

Stells [14]

1?....................

8 0

3 years ago

At 700 K, the reaction 2SO2(g) + O2(g) <====> 2SO3(g) has the equilibrium constant Kc = 4.3 x 106. At a certain instant, f

nadya68 [22]

Answer:

The system is not in equilibrium and will evolve left to right to reach equilibrium.

Explanation:

The reaction quotient Qc is defined for a generic reaction:

aA + bB → cC + dD

$Q=\frac{[C]^{c} *[D]^{d} }{[A]^{a}*[B]^{b} }$

where the concentrations are not those of equilibrium, but other given concentrations

Chemical Equilibrium is the state in which the direct and indirect reaction have the same speed and is represented by a constant Kc, which for a generic reaction as shown above, is defined:

$Kc=\frac{[C]^{c} *[D]^{d} }{[A]^{a}*[B]^{b} }$

where the concentrations are those of equilibrium.

This constant is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients divided by the multiplication of the concentrations of the reactants also raised to their stoichiometric coefficients.

Comparing Qc with Kc allows to find out the status and evolution of the system:

If the reaction quotient is equal to the equilibrium constant, Qc = Kc, the system has reached chemical equilibrium.

If the reaction quotient is greater than the equilibrium constant, Qc> Kc, the system is not in equilibrium. In this case the direct reaction predominates and there will be more product present than what is obtained at equilibrium. Therefore, this product is used to promote the reverse reaction and reach equilibrium. The system will then evolve to the left to increase the reagent concentration.

If the reaction quotient is less than the equilibrium constant, Qc <Kc, the system is not in equilibrium. The concentration of the reagents is higher than it would be at equilibrium, so the direct reaction predominates. Thus, the system will evolve to the right to increase the concentration of products.

In this case:

$Q=\frac{[So_{3}] ^{2} }{[SO_{2} ]^{2}* [O_{2}] }$

$Q=\frac{10^{2} }{0.10^{2} *0.10}$

Q=100,000

100,000 < 4,300,000 (4.3*10⁶)

Q < Kc

The system is not in equilibrium and will evolve left to right to reach equilibrium.

3 0

3 years ago

Consider the reaction directly below and answer parts a and b. C6H4(OH)2 (l) + H2O2 (l) à C6H4O2 (l) + 2 H2O (l)

dedylja [7]

Answer:

a. -206,4kJ

b. Surroundings will gain heat.

c. -115kJ are given off.

Explanation:

It is possible to obtain ΔH of a reaction using Hess's law that consist in sum the different ΔH's of other reactions until obtain the reaction you need.

Using:

(1) C₆H₄(OH)₂(l) → C₆H₄O₂(l) + H₂(g) ΔH: +177.4 kJ

(2) H₂(g) + O₂(g) → H₂O₂ (l) ΔH: -187.8 kJ

(3) H₂(g) + 1/2O₂(g) → H₂O(l) ΔH: -285.8 kJ

It is possible to obtain:

C₆H₄(OH)₂(l) + H₂O₂(l) → C₆H₄O₂(l) + 2H₂O(l)

From (1)-(2)+2×(3). That is:

(1) C₆H₄(OH)₂(l) → C₆H₄O₂(l) + H₂(g) ΔH: +177.4 kJ

-(2) H₂O₂(l) → H₂(g) + O₂(g) ΔH: +187.8 kJ

2x(3) 2H₂(g) + O₂(g) → 2H₂O(l) ΔH: 2×-285.8 kJ

The ΔH you obtain is:

+177,4kJ + 187,8kJ - 2×285.8 kJ = -206,4kJ

b. When ΔH of a reaction is <0, the reaction is exothermic, that means that the reaction produce heat and the surroundings will gain this heat.

c. 20,0g of H₂O are:

20,0g× $\frac{1mol}{18,01g}$ = 1,11 mol H₂O

As 2 moles of H₂O are produced when -206,4kJ are given off, when 1,11mol of H₂O are produced, there are given off:

1,11mol H₂O× $\frac{-206,4kJ}{2mol}$ = -115kJ

I hope it helps!

8 0

3 years ago

The enzyme, carbonic anhydrase, is a large zinc-containing protein with a molar mass of 3.00 x10^4 g/mol. Zn is 0.218% by mass o

tia_tia [17]

The mathematical expression for mass percent is given by:

$Mass percent = \frac{mass of the compound}{molar mass of the compound}\times 100$

Put the values,

$0.218 percent of zinc = \frac{mass of zinc}{3.00 \times 10^{4} g/mol}\times 100$

mass of zinc = $0.218 \times (3\times 100) g$

= $0.654 \times 100 g$ or 65.4 g

Now, number of moles of zinc = $\frac{given mass in g}{molar mass of zinc}$

= $\frac{65.4 g}{65.38 g/mol}$

= 1.00 mole

Number of atoms of zinc is calculated by the Avogadro number.

Now, according to mole concept

$6.022\times 10^{23}$ molecules of enzyme consists of $6.022\times 10^{23}$ atoms of zinc

So, 1 molecule of enzyme contains = $\frac{6.022\times 10^{23}atoms of zinc}{6.022\times 10^{23} }$

= 1 atom of zinc.

Hence, every carbonic anhydrase molecule consists of 1 atom of zinc.

5 0

3 years ago

PLEASE HELP!!!

Inga [223]

Answer:

$d=1.5\ g/cm^3$

Explanation:

Given that,

The mass of the rock, m = 15 g

The volume of the rock, V = 10 cm³

We need to find the density of the rock. The density of an object is equal to the mass per unit volume such that,

$d=\dfrac{m}{V}\\\\d=\dfrac{15\ g}{10\ cm^3}\\\\d=1.5\ g/cm^3$

So, the density of the rock is equal to $1.5\ g/cm^3$ .

3 0

3 years ago