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3 years ago

Please Help Q 4.How many moles are there in 2.4 x 10 24 atoms of He?

Chemistry

2 answers:

liubo4ka [24]3 years ago

6 0

(2.4 x 10 24) divided by (6 x 10 23)=

a_sh-v [17]3 years ago

5 0

Answer: 4moles

Explanation:

1mole of He contain 6.02x10^23 atoms.

Xmol of He will contain 2.4 x 10^24 atoms i.e

Xmol of He = 2.4x10^24/6.02x10^23 = 4mol

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For the reaction A+B+C→D+E, the initial reaction rate was measured for various initial concentrations of reactants. The followin

erastovalidia [21]

Answer : The initial rate for a reaction will be $3.4\times 10^{-3}Ms^{-1}$

Explanation :

Rate law is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.

For the given chemical equation:

$A+B+C\rightarrow D+E$

Rate law expression for the reaction:

$\text{Rate}=k[A]^a[B]^b[C]^c$

where,

a = order with respect to A

b = order with respect to B

c = order with respect to C

Expression for rate law for first observation:

$6.0\times 10^{-5}=k(0.20)^a(0.20)^b(0.20)^c$ ....(1)

Expression for rate law for second observation:

$1.8\times 10^{-4}=k(0.20)^a(0.20)^b(0.60)^c$ ....(2)

Expression for rate law for third observation:

$2.4\times 10^{-4}=k(0.40)^a(0.20)^b(0.20)^c$ ....(3)

Expression for rate law for fourth observation:

$2.4\times 10^{-4}=k(0.40)^a(0.40)^b(0.20)^c$ ....(4)

Dividing 1 from 2, we get:

$\frac{1.8\times 10^{-4}}{6.0\times 10^{-5}}=\frac{k(0.20)^a(0.20)^b(0.60)^c}{k(0.20)^a(0.20)^b(0.20)^c}\\\\3=3^c\\c=1$

Dividing 1 from 3, we get:

$\frac{2.4\times 10^{-4}}{6.0\times 10^{-5}}=\frac{k(0.40)^a(0.20)^b(0.20)^c}{k(0.20)^a(0.20)^b(0.20)^c}\\\\4=2^a\\a=2$

Dividing 3 from 4, we get:

$\frac{2.4\times 10^{-4}}{2.4\times 10^{-4}}=\frac{k(0.40)^a(0.40)^b(0.20)^c}{k(0.40)^a(0.20)^b(0.20)^c}\\\\1=2^b\\b=0$

Thus, the rate law becomes:

$\text{Rate}=k[A]^2[B]^0[C]^1$

Now, calculating the value of 'k' by using any expression.

Putting values in equation 1, we get:

$6.0\times 10^{-5}=k(0.20)^2(0.20)^0(0.20)^1$

$k=7.5\times 10^{-3}M^{-2}s^{-1}$

Now we have to calculate the initial rate for a reaction that starts with 0.75 M of reagent A and 0.90 M of reagents B and C.

$\text{Rate}=k[A]^2[B]^0[C]^1$

$\text{Rate}=(7.5\times 10^{-3})\times (0.75)^2(0.90)^0(0.90)^1$

$\text{Rate}=3.4\times 10^{-3}Ms^{-1}$

Therefore, the initial rate for a reaction will be $3.4\times 10^{-3}Ms^{-1}$

8 0

3 years ago

Texture provides clues about how igneous rocks were formed A. true B. False

hammer [34]

A.) true

Because the rocks are formed near lava so the texture would be smooth

3 0

3 years ago

How do we use properties of matter in our every day lives

bearhunter [10]

For example, water. In its liquid state we drink it , in its solid state (ice ) we use it to make our drinks colder or t numbs pain when wrapped in cloth and it’s gas state ( water vapour) we steam vegetables. In conclusion many different properties of matter are used for various purposes

6 0

4 years ago

What is the mass of an osmium block that measures 6.70 cm × 9.20 cm × 3.30 cm? The density of osmium is given as 22.610 g/cm3. N

alexira [117]

Answer:

m= 4,599.145 g

Explanation:

Let m = mass, d = density and V = volume of the osmium block.

m = d x V

m = 22.610 g/cm3 x (6.70 x 9.20 x 3.3) cm3

m = 4,599.145 g

7 0

3 years ago

A chemical plant produces ammonia using the following reaction at a very high temperature and pressure. Which design issue is mo

Lorico [155]

Answer:

D. The equipment needed to accommodate the high temperature and pressure will be expensive to produce.

Explanation:

Hello!

In this case, for the considered reaction, it is clear it is an exothermic reaction because it produces energy; and therefore, the higher the temperature the more reactants are yielded as the reverse reaction is favored. Moreover, since the effect of pressure is verified as favoring the side with fewer moles; in this case the products side (2 moles of ammonia).

In such a way, the high pressure favors the formation of ammonia whereas the high temperature the formation of hydrogen and nitrogen and therefore, option A is ruled out. Since the high pressure shifts the reaction rightwards and the high temperature leftwards, we would not be able to know whether the reaction has ended or not because it will be a "go and come back" process, that is why B is also discarded. Now, since hydrogen and nitrogen would be the "wastes", we discard C because they are not toxic. That is why the most accurate answer would be D. because it is actually true that such equipment is quite expensive.

Best regards!

6 0

3 years ago