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3 years ago

What scientist do that basis for their investigation

1 answer:

4 0

Maybe formulate a hypothesis....
Do you mean like what is the core for investigation?
Variable are factors that influence our observation for investigation.

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The normal boiling point of a substance occurs when its vapor pressure is 1.00 atm, which means that at this temperature, the li

Sladkaya [172]

Answer:

See explanation below

Explanation:

For start, we need some values here to do this exercise.

In general, you can calculate the normal boiling point of any substance by using the Clausius Clapeyron equation which is the following:

ln(P2/P1) = -ΔHvap/R (1/T2 - 1/T1)

Where:

P1 and P2: pressure of the substance at T1 and T2.

ΔHvap: enthalpy of vaporization of the substance. In the case of bromine is 29.6 kJ/mol

R: constant gas. In this case is 8.3145 J/mol K

T1 and T2: temperature of the substance.

In order to calculate the normal boiling point, we will assign that value to T2, and the pressure would be 1 atm or 1.01x10^5 Pa

T1 and P1 would be temperature and pressure of this substance at any condition. For this example, I will take the fact that Bromine has 22000 Pa at 20 °C (or 293.15 K)

With this data, let's replace in the clausius Clapeyron equation:

ln(1.01x10^5 / 22000) = -29600/8.3145 (1/T2 - 1/293.15)

-1.5241 * 8.3145 / 29600 = (1/T2 - 1/293.15)

-4.281x10^-4 + 1/293.15 = 1/T2

T2 = 1 / 2.9831x10^-3

T2 = 335.22 or 62.07 °C

The real one is 59 °C so, the difference in the result may come with the values of P1 and T1 that may be not accurate.

7 0

3 years ago

In the following reaction, which are the products?

myrzilka [38]

Answer: H2 + MgCl2

Explanation: As they are on the right side of the equation/ are the products being made as a result of the reaction, they are the products.

5 0

3 years ago

Decide which of the following statements are True and which are False about equilibrium systems:A large value of K means the equ

ivanzaharov [21]

Answer:

a. True

b. False

c. True

d. False

e. False

Explanation:

A. (true) The equilibrium constant K is defined as

$\frac{Products}{reagents}$

In any case

aA +Bb ⇌ Cd +dD

where K is:

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

A large value on K means that the concentration of products is bigger than the concentrations of reagents, so the forward reaction is favored, and the equilibrium lies to the right.

B. (False) When we work with gases, we use partial pressure to make calculations in the equilibrium, so we estimate Kp as:

$Kp= \frac{(P_{C})^{c}(P_{D})^{d}}{(P_{A})^{a}(P_{B})^{b}}$

Using the ideal gas law, we can get a relationship between K and Kp

Pv=nRT where $P=\frac{n}{v}*RT$ we know that $\frac{n}{v}$ is the molar concentration. When we replace P in the expression for Kp we get:

$Kp= \frac{[C]^{c}*(RT)^{c}[D]^{d}*(RT)^{d}}{[A]^{a}*(RT)^{a}[B]^{b}*(RT)^{b}}$

Reorganizing the equation:

$Kp= \frac{[C]^{c}[D]^{d}}{[A]^{a}[B]^{b}}*\frac{(RT)^{c+d}}{(RT)^{a+b}}$

We can see K in the expression

$Kp= K*(RT)^{c+d-a-b}$

Delta n = c+d-a-b

$Kp= K*(RT)^{delta n}$

For the reaction

$H_{2}(g) + F_{2}(g)-- equilibrium---2HF(g)$

Delta n = 2-1-1=0

$Kp= K*(RT)^{0}$

So Kp=K in this case.

C. (true) The value of K just depends on the temperature that’s why changing the among of products won’t have any effect on its value.

D. (false) as we can see this reaction involve a heterogeneous system with solids and gases. For convention the concentration for solids and liquids can be considered constant during the reaction that’s why they’re not include in the calculation for the equilibrium constant. Taking this into account the expression for the equilibrium for this reaction is:

$CaCO_{3}(s)---equilibrium----CaO(s) + CO_{2}(g)$

$K= [CO_{2}]$

So we can see that $[CaCO_{3}]$ is not include in the expression.

E. (False) The equilibrium is defined as the point where the rate of the forward reaction is the same to the rate of the reverse reaction. The value of K is telling you which reaction is favored but the rate of both reactions is the same in this point. (see picture)

3 0

3 years ago

In the reaction HCl + KOH ® KCl+ H2O, the spectator ions are:

Lilit [14]

Spectator ions are zero(0) due to change of chemical reaction and absence of ions above the compound.

4 0

3 years ago

Sodium hydride reacts with excess water to produce aqueous sodium hydroxide and hydrogen gas:NaH (s) H2O (l) → NaOH (aq) H2 (g)A

Anuta_ua [19.1K]

NaH(s)+ H2O (l)=>NaOH(aq)+H2(g)

You want to calculate the mass of NaH, I assume. Otherwise, the question isn't clear. It simply says calculate the mass(??)

So, calculate the moles of H2 gas that satisfy the conditions of 982 ml at 28ºC and 765 torr. But you must subtract the vapor pressure of water at 28º to get the actual pressure of the H2 gas. So, the actual conditions are 982 ml (0.982 L) and 301 K and 765-28 = 737 torr.

PV = nRT

n = PV/RT = (737 torr)(0.982 L)/(62.4 L-torr/Kmol)(301 K)

n = 0.0385 moles H2

moles NaH needed = 0.0385 moles H2 x 1 mole NaH/mole H2 = 0.0385 moles NaH required

mass of NaH needed = 0.0385 moles x 24 g/mole = 0.925 g NaH

Brainliest Please :)

7 0

4 years ago

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