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2 years ago

Al wonders if adding salt to water will affect how long it takes the water to

Chemistry

1 answer:

love history [14]2 years ago

6 0

The hypothesis is that salt water freezes faster than fresh water.

The dependent variable is time taken for ice to appear.

The independent variable is presence or absence of salt

The constants are the amount of water in each tray, freezing conditions and length of time of exposure to freezing condition.

The control group is the tray to which salt was not added

The experimental group is the tray to which salt was added

The presence of solutes in a solution causes the freezing point depression.

A solution is made up of a solute and a solvent. In the presence of a solute, the freezing point of a pure solvent is decreased. This is because freezing point is a colligative property.

Colligative properties depend on the amount of solute present.

Hence, the pure water freezes faster (ice begin to appear earlier) than the salt water.

The hypothesis put forward in this experiment was found to be invalid by the experiment.

For more about colligative properties, see

brainly.com/question/10323760

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Be sure to answer all parts. The equilibrium constant (Kp) for the reaction below is 4.40 at 2000. K. H2(g) + CO2(g) ⇌ H2O(g) +

nikklg [1K]

Answer:

For 1: The value of $\Delta G$ for the chemical equation is -24.636 kJ/mol

For 2: The value of $\Delta G$ for the chemical equation is -20.925 kJ/mol

Explanation:

For the given chemical equation:

$H_2(g)+CO_2(g)\rightleftharpoons H_2O(g)+CO(g)$

For 1:

To calculate the $\Delta G$ for given value of equilibrium constant, we use the relation:

$\Delta G=-RT\ln K_p$ .....(1)

where,

$\Delta G$ = ? kJ/mol

R = Gas constant = $8.314J/K mol$

T = temperature = 2000 K

$K_p$ = equilibrium constant in terms of partial pressure = 4.40

Putting values in above equation, we get:

$\Delta G=-(8.314J/Kmol)\times 2000K\times \ln (4.40)\\\\\Delta G=-24636.12J/mol$

Converting this into kilo joules, we use the conversion factor:

1 kJ = 1000 J

So, -24636.12 J/mol = -24.636 kJ/mol

Hence, the value of $\Delta G$ for the chemical equation is -24.636 kJ/mol

For 2:

The expression of $K_p$ for the given chemical equation is:

$K_p=\frac{p_{CO}p_{H_2O}}{p_{H_2}p_{CO_2}}$

We are given:

$p_{CO}=1.18atm\\p_{H_2O}=0.66atm\\p_{CO_2}=0.82atm\\p_{H_2}=0.27atm$

Putting values in above equation, we get:

$K_p=\frac{1.18\times 0.66}{0.27\times 0.82}\\\\K_p=3.52$

Now, calculating the value of $\Delta G$ by using equation 1:

R = Gas constant = $8.314J/K mol$

T = temperature = 2000 K

$K_p$ = equilibrium constant in terms of partial pressure = 3.52

Putting values in equation 1, we get:

$\Delta G=-(8.314J/Kmol)\times 2000K\times \ln (3.52)\\\\\Delta G=-20925.68J/mol$

Converting this into kilo joules, we use the conversion factor:

1 kJ = 1000 J

So, -20925.68 J/mol = -20.925 kJ/mol

Hence, the value of $\Delta G$ for the chemical equation is -20.925 kJ/mol

3 0

3 years ago

Read 2 more answers

Breeder reactors are used to convert the nonfissionable nuclide U-238 to a fissionable product. Neutron capture by the U-238 is

m_a_m_a [10]

Answer:

Pu-239

Explanation:

Beta decay moves the element which undergoes the decay one place to the right in the periodic table since to conserve charge and being beta radiations an electron we convert a neutron into a proton and an electron. In neutron capture we increase the atomic mas by one unit. We that in mind, lets solve the question:

U-238 + ₁⁰ n ⇒ U-239 ⇒ Np -239 + ₋₁⁰β ⇒ Pu-239 + ₋₁⁰β

7 0

3 years ago

What is the independent, dependent, and controlled variable?

attashe74 [19]

Independent Variable: amount of sunlight given

Dependent Variable: How tall the plants grow

Control: The plant given no sunlight

7 0

3 years ago

Rr- Bb- rr- Heterogeneous long nose- PLEASE

alexdok [17]

Answer:

Rr.. eye shape

rr... oval

Bb ,,,, square pants

8 0

3 years ago

Read 2 more answers

a sample of ammonia liberates 5.66 kj of heat as it solidifies at its melting point . what is the mass of the sample?

Reil [10]

The correct answer for the question that is being presented above is this one: "16.728 g."

Given that
ΔHsolid = -5.66 kJ/mol.
This means that 5.66 kJ of heat is released when 1 mole of NH3 solidifies

When 5.57 kJ of heat is released
amount of NH3 solidifies = 5.57/5.66 = 0.984 moles

molar mass of NH3 = 17 g/mole 
1 mole of NH3 = 17 g 
So, 0.984 moles of NH3 = 17 X 0.984 = 16.728 g

7 0

3 years ago