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3 years ago

Which of the following are not molecules? A. MgCl₂ B. C₃H₈ C. Al D. NaCl E. Ag

Chemistry

1 answer:

xxMikexx [17]3 years ago

5 0

Answer:

C.Al & E. Ag

Explanation:

These two are elements. Meaning tget are substances that cannot be broken down because they are pure. The others are considered molecules due to their ability to be broken down.

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Be sure to answer all parts. Write the balanced equations corresponding to the following rate expressions: a) rate = − 1 3 Δ[CH4

Alinara [238K]

Answer : The balanced equations will be:

(a) $3CH_4+2H_2O+CO_2\rightarrow 4CH_3OH$

(b) $2N_2O_5\rightarrow 2N_2+5O_2$

(c) $2H_2+2CO_2+O_2\rightarrow 2H_2CO_3$

Explanation :

The general rate of reaction is,

$aA+bB\rightarrow cC+dD$

Rate of reaction : It is defined as the change in the concentration of any one of the reactants or products per unit time.

The expression for rate of reaction will be :

$\text{Rate of disappearance of A}=-\frac{1}{a}\frac{d[A]}{dt}$

$\text{Rate of disappearance of B}=-\frac{1}{b}\frac{d[B]}{dt}$

$\text{Rate of formation of C}=+\frac{1}{c}\frac{d[C]}{dt}$

$\text{Rate of formation of D}=+\frac{1}{d}\frac{d[D]}{dt}$

$Rate=-\frac{1}{a}\frac{d[A]}{dt}=-\frac{1}{b}\frac{d[B]}{dt}=+\frac{1}{c}\frac{d[C]}{dt}=+\frac{1}{d}\frac{d[D]}{dt}$

From this we conclude that,

In the rate of reaction, A and B are the reactants and C and D are the products.

a, b, c and d are the stoichiometric coefficient of A, B, C and D respectively.

The negative sign along with the reactant terms is used simply to show that the concentration of the reactant is decreasing and positive sign along with the product terms is used simply to show that the concentration of the product is increasing.

Now we have to determine the balanced equations corresponding to the following rate expressions.

(a) $Rate=-\frac{1}{3}\frac{d[CH_4]}{dt}=-\frac{1}{2}\frac{d[H_2O]}{dt}=-\frac{d[CO_2]}{dt}=+\frac{1}{4}\frac{d[CH_3OH]}{dt}$

The balanced equations will be:

$3CH_4+2H_2O+CO_2\rightarrow 4CH_3OH$

(b) $Rate=-\frac{1}{2}\frac{d[N_2O_5]}{dt}=+\frac{1}{2}\frac{d[N_2]}{dt}=+\frac{1}{5}\frac{d[O_2]}{dt}$

The balanced equations will be:

$2N_2O_5\rightarrow 2N_2+5O_2$

(c) $Rate=-\frac{1}{2}\frac{d[H_2]}{dt}=-\frac{1}{2}\frac{d[CO_2]}{dt}=-\frac{d[O_2]}{dt}=+\frac{1}{2}\frac{d[H_2CO_3]}{dt}$

The balanced equations will be:

$2H_2+2CO_2+O_2\rightarrow 2H_2CO_3$

4 0

3 years ago

The specific heat of a given substance

Lelechka [254]

The specific heat is the amount of heat per unit mass required to raise the temperature to 1 degree Celsius. (This is from google)

7 0

3 years ago

Given that a 19.00 g milk chocolate bar contains 11.50 g of sugar, calculate the percentage of sugar present in 19.00

Jet001 [13]

Explanation:

check the steps in the attached image

6 0

2 years ago

What process in the carbon cycle takes carbon out of air?

Veronika [31]

It is photosynthesis

photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct, hope it helps

7 0

3 years ago

Calculate the amount of energy required to increase the temperature of 18.0 go vapor water from 275.0 degrees * C to 385 degrees

Archy [21]

Answer:

The amount of energy required to increase temperature 275°C to 385°C is ΔQ =3.95208kJ

Explanation:

Given :

The mass of the water vapour is 18 g
The initial temperature : 275°C
The final temperature : 385°C

According to the formula :

Δ $Q = m*s*$ Δ $T$

Where ,

Δ $Q$ is the heat supplied
$m$ is the mass of the substance (water vapour) = 18g
$s$ is the specific heat of the substance ( water vapour) = $1.996Jg^{-1}K^{-1}$
Δ $T$ is the change in temperature = $385-275=110K$

∴

ΔQ = $18*1.996*110\\=3952.08J$

⇒ΔQ =3.95208kJ

8 0

4 years ago