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3 years ago

What is the new boiling point if 25 g of NaCl is dissolved in 1.0 kg of water

1 answer:

8 0

The correct answer for the question that is being presented above is this one:

Given that:
delta Tb = Kbm Kb H2O = 0.52 degrees C/m
delta Tf = Kfm Kf H2O = 1.86 degrees C/m

We need to know the formula for Molality.
molality = mol solute / kg solvent

We are given the amount of solute in grams
Since amount of solute is given in moles, we have to convert 25 g NaCl to moles. Divide by molar mass. 

25 g NaCl / 58.5 g/mol = 0.427 mol 

Then, use the formula for molality. 

molality = mol solute / kg solvent 
= 0.427 / 1 
= 0.427 m 

Use now the formula to get the boiling point.

delta Tb = Kbm 
= (0.52)(0.427) 
= 0.22C

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Dvinal [7]

Answer:

The answer will be ：

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7 0

2 years ago

The permanent electric dipole moment of the water molecule 1H2O2 is 6.2 * 10-30 C m. What is the maximum possible torque on a wa

stellarik [79]

Answer:

3.1 x 10⁻²¹ Nm

Explanation:

When placed in an external electric filed, an electric dipole experiences a torque. and this torque is represented mathematically with the equation:

torque (τ) = dipole moment vector (P) x electric field vector (E)

τ = P. E . sin θ

where θ is the angle between the water molecule and the electric field, which in this case is 90° (because this is where the torque is maximum)

τ = 6.2x10⁻³⁰Cm . 5.0x10⁸ N/C . sin90

τ = 6.2x10⁻³⁰Cm . 5.0x10⁸ N/C . 1

solve for τ

τ = 3.1 x 10⁻²¹ Nm

the maximum possible torque on the water molecule is therefore 3.1 x 10⁻²¹ Nm

7 0

3 years ago

Certain drugs, such as ssris, block the reuptake of a neurotransmitter into the presynaptic cell. what effect does this have ons

Sloan [31]

Selective serotonin reuptake inhibitors (SSRIs) are drugs that are antidepressants. These blocks the reuptake of a neurotransmitter leading to increases in their activity in the synaptic cells.

<h3>What are neurotransmitters?</h3>

Neurotransmitters are defined as the signaling molecules that are secreted by the nerve cells and act as signal transporter between the neurons and the other cells of the body.

The SSRIs class of drugs affects this neurotransmitter and blocks the pathway to the presynaptic cell. This, in turn, affects synaptic communication by increasing the amount of those SSRIs in the body and acting as a stimulant to treat various diseases.

Therefore, the SSRIs block the neurotransmitter and result in their effects.

Learn more about neurotransmitters here:

brainly.com/question/28138251

#SPJ4

6 0

1 year ago

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

2. Fe(s) + O2(g) → Fe3O4(s) a. When 13.54 g of O2 is mixed with 12.21 g of Fe, which is the limiting reactant? b. What mass in g

julsineya [31]

The percent yield shows the extent to which the reactants are converetd into products . The limiting reactant is used up in the reaction.

<h3>What is a limiting reactant?</h3>

A limiting reactant is the reactant that is in the least amount in the system. Now;

Number of moles of Fe = 12.21 g/56 g/mol = 0.22 moles

Number of moles of O2 = 13.54 g/32 g/mol = 0.42 moles

Balanced reaction equation;

3Fe(s) + 2 O2(g) = Fe3O4(s)

If 3 moles of Fe reacts with 2 mole of O2

0.22 moles of Fe reacts with 0.22 moles * 2 mole/3 moles = 0.15 moles

Hence, Fe is the limiting reactant

If 3 mole of Fe produces 1 mole of Fe3O4(s)

0.22 moles of O2 produces 0.22 moles * 1 mole/3 moles of Fe3O4(s) = 0.1073 moles

Mass of Fe3O4(s) =0.1073 moles * 232 g/mol =16.9 g

Number of moles of excess reactant = 0.42 moles - 0.15 moles = 0.27 moles

Mass of excess reactant = 0.27 moles * 32 g/mol = 8.64 g

percent yield = 15.88 g/16.9 g * 100/1

= 93.4%

Learn more about percent yiled: brainly.com/question/13463225

8 0

2 years ago