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3 years ago

Knowing the chemical properties of a substance will tell you how the substance

2 answers:

8 0

<span>Whereas physical properties of a substance tells us about how the substance looks, smells, etc, the chemical properties of a substance basically tells us how the substance will react with other substances. Therefore, knowing the chemical property of a substance tells us how the substance reacts with others.Hope this helps. Let me know if you need additional help!</span><span />

NikAS [45]3 years ago

6 0

D. reacts with other substances.

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A gas occupies 200ml at a temperature of 26 degrees Celsius and 76mmHg pressure. Find the volume at -3degree Celsius with the pr

sergey [27]

Answer:

184.62 ml

Explanation:

Let $p_1, v_1,$ and $T_1$ be the initial and $p_2, v_2,$ and $T_2$ be the final pressure, volume, and temperature of the gas respectively.

Given that the pressure remains constant, so

$p_1=p_2$ ...(i)

$v_1$ = 200 ml

$T_1= 26 ^{\circ}C = 273+26 =299$ K

$T_2= 3 ^{\circ}C = 273+3 =276$ K

From the ideal gas equation, pv=mRT

Where p is the pressure, v is the volume, T is the temperature in Kelvin, m is the mass of air in kg, R is the specific gas constant.

For the initial condition,

$p_1v_1=mRT_1 \\\\mR= \frac{p_1v_1}{T_1}\cdots(ii)$

For the final condition,

$p_2v_2=mRT_2 \\\\mR= \frac{p_2v_2}{T_2}\cdots(iii)$

Equating equation (i), and (ii)

$\frac{p_1v_1}{T_1}=\frac{p_2v_2}{T_2}$

$\frac{v_1}{T_1}=\frac{v_2}{T_2}$ [from equation (i)]

$v_2=\frac{T_2}{T_1} \times v_1$

Putting all the given values, we have

$v_2=\frac{276}{299} \times 200 = 184.62 \; ml$

Hence, the volume of the gas at 3 degrees Celsius is 184.62 ml.

7 0

3 years ago

Chemical reactions are only able to occur in one direction. Chemical reactions are only able to occur in one direction. True Fal

blagie [28]

Answer:

False

Explanation:

While chemical reactions can proceed in the forward direction , they can in fact also proceed in the backward direction too. The direction they would proceed depends majorly on the state of chemical equilibrium at that particular time for that particular chemical reaction.

It should be known that when a chemical reaction proceeds in the forward way, more products are formed and the reactants are used up. If however, the chemical reaction proceed in the backward way, more reactants are formed and the products are used up.

A practical example is in the case of an exothermic reaction. This is one in which heat is released to the surroundings as a result of the reactants being at a higer energy level compared to the product. Now, depending on the prevailing equilibrium constraint, the reaction could proceed forward or backward.

If for example, the temperature is decreased, this is a constraint being applied to the equilibrium state. The chemical reaction would take a shift and will favor the forward reaction and more of the products will be formed. And also of the temperature is increased, it is the backward reaction that is favored

7 0

3 years ago

A second- order reaction of the type A + B -->P was carried out in a solution that was initially 0.075 mol dm^-3 in A and 0.0

andriy [413]

Answer:

a) 16.2 dm^3/mol*h

b) 6.1 × 10^3 s, 2.5 × 10^3 s (it is different to the hint)

Explanation:

We can use the integrated rate equation in order to obtain k.

For the reaction A+ B --> P the reaction rate is written as

Rate = $-\frac{dC_A}{dt} = -\frac{dC_B}{dt} = \frac{dC_P}{dt} = kC_AC_B$

If $C_{A0}$ and $C_{B0}$ are the inital concentrations and x the concentration reacted at time t, so $C_A=C_{A0} -x$ and $C_B=C_{B0} -x$ and the rate at time t is written as:

$-\frac{dx}{dt} =-k(C_{A0} -x)(C_{B0}-x)$

Separating variables and integrating

$\int\limits^x_0 {\frac{1}{(C_{A0}-x)(C_{B0}-x)} } \, dx = \int\limits^t_0 {k} \, dt$

The integral in left side is solved by partial fractions, it can be used integral tables

$\frac{1}{C_{B0}-C_{A0}}(ln\frac{C_{A0}}{C_{A0}-x}-ln\frac{C_{B0}}{C_{B0}-x}) =kt$

Using logarithm properties (ln x - ln y = ln(x/y))

$\frac{1}{C_{B0}-C_{A0}}(ln\frac{C_{A0}C_{B}}{C_{A}C_{B0}}) =kt$

Using the given values k can be calculated. But the data seems inconsistent since if the concentration of A changes from 0.075 to 0.02 mol dm^-3 it implies that 0.055 mol dm^-3 of A have reacted after 1 h, so according to the reaction given the same quantity of B should react, and we only have a $C_{B0}$ of 0.05 mol dm^-3.

Assuming that the concentration of B fall to 0.02 mol dm^-3 (and not the concentration the A). So we arrive to the answer given in the Hint.

So, the values given are t= 1, $C_{A0}=0.075$ , $C_{B0}=0.05$ , $C_{B}=0.02$ , it implies that the quantity reacted, x, is 0.03 and $C_{A}=0.075-x = 0.045$ . Then, the value of k would be

$kt = \frac{1}{0.05-0.075}(ln\frac{0.075*0.02}{0.045*0.05})$

$k = 16.21 \frac{dm^3}{mol*1h}$

b) the question b requires calculate the time when the concentration of the specie is half of the initial concentration.

For reactant A, It is solved with the same equation

$\frac{1}{C_{B0}-C_{A0}}(ln\frac{C_{A0}C_{B}}{C_{A}C_{B0}}) =kt$

but suppossing that $C_A= C_{A0}/2=0.0375$ so $C_B=C_{B0}- C_{A0}/2=0.0125$ , k=16.2 and the same initial concentrations. Replacing in the equation

$t=\frac{1}{16.2(0.05-0.075)}(ln\frac{0.075*0.0125}{0.0375*0.05})$

$t=1.71 h = 1.71*3600 s = 6.1*10^3 s$

For reactant B, $C_B= C_{B0}/2=0.025$ so $C_A=C_{A0}- C_{B0}/2=0.05$ , k=16.2 and the same initial concentrations. Replacing in the equation

$t=\frac{1}{16.2(0.05-0.075)}(ln\frac{0.075*0.025}{0.05*0.05})$

$t=0.71 h = 0.7*3600 s = 2.5*10^3 s$

Note: The procedure presented is correct, despite of the answer be something different to the given in the hint, I obtain that result if the k is 19.2... (maybe an error in calculation of given numbers)

3 0

3 years ago

There are 12 liters of nitrogen gas in a sample. How many moles of N2 in this sample?

Firlakuza [10]

Answer:

0.54 moles of N2

Explanation:

First remember to find the volume in moles, 1 mole equals 22.4 liters.

So now use the dimensional analysis to show your work.

12 liters of N2 * 1 mol /22.4 liters of N2

Now calculate this. 12 * 1/22.4 or 12/ 22.4

12/22.4 = 0.535714286.

12 has two significant digits.

With that, The answer rounds to 0.54.

So that the final answer is 0.54 moles.

Hope it helped!

6 0

3 years ago

What is meant by the following statement?

Yanka [14]

Answer:

Explanation:

Inverse and proportional means as one goes up the other goes up or if one goes down the other goes down.

- Hope that helped! Please let me know if you need further explanation.

6 0

3 years ago

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