What is used to kill cavities

The freezing point of a nonelectrolyte solution containing 30.0 g of a solute dissolved in 250.0 g of water is observed to be -2

scZoUnD [109]

Answer:

Molar mass of solute is 89.28 g/m

Explanation:

Colligative property of freezing point depression to solve this:

ΔT = Kf . m . i

i = number of particles, dissolved in solution. In this case, it is a nonelectrolyte, so i = 1.

m = molalilty (mol of solute/1kg of solvent

ΔT = T° freeze pure solvent - T° freeze solution

0°C - (-2.50°C) = 1.86 °C/m . m

2.50°C / 1.86 m/°C = m

1.34 mol solute/kg solvent = m

This means, that in 1000 g of solvent, we have 1.34 moles but we have 250 g of solvent, so let's make a rule of three.

1000 g ____ 1.34 moles

250 g _____(2.50 . 1.34) / 1000 = 0.336 moles

To find the molar mass, we divide mass / moles

30 g/ 0.336 moles = 89.28 g/m

7 0

3 years ago

A sample of gas contains 0.1800 mol of CO(g) and 0.1800 mol of NO(g) and occupies a volume of 23.2 L. The following reaction tak

baherus [9]

Answer:

The volume of the sample is 17.4L

Explanation:

The reaction that occurs requires the same amount of CO and NO. As the moles added of both reactants are the same you don't have any limiting reactant. The only thing we need is the reaction where 4 moles of gases (2mol CO + 2mol NO) produce 3 moles of gases (2mol CO2 + 1mol N2). The moles produced are:

0.1800mol + 0.1800mol reactants =

0.3600mol reactant * (3mol products / 4mol reactants) = 0.2700 moles products.

Using Avogadro's law (States the moles of a gas are directly proportional to its pressure under constant temperature and pressure) we can find the volume of the products:

V1n2 = V2n1

<em>Where V is volume and n moles of 1, initial state and 2, final state of the gas</em>

Replacing:

V1 = 23.2L

n2 = 0.2700 moles

V2 = ??

n1 = 0.3600 moles

23.2L*0.2700mol = V2*0.3600moles

17.4L = V2

<h3>The volume of the sample is 17.4L</h3>

8 0

2 years ago

2. Calculate the joules of energy required to heat 454.3g of water<br> frum 5.4°C to 98.6°C.

Tasya [4]

Answer:

176984.38J

Explanation:

E = mC∆T

Where E is the energy in joules

M is the mass of water

C is the specific heat capacity of water =4.184J/g°C

It is known that it will take 4.184J of energy to change the temperature of water by one degree Celsius.

∆T = 98.6°c - 5.4°c

= 93.2°c

∆H = 454.3g × 4.18J/g°C × 93.2°c

= 176984.3768

176984.38J

7 0

3 years ago

"A sphere of radius 0.50 m, temperature 27oC, and emissivity 0.85 is located in an environment of temperature 77oC. What is the

Aleksandr-060686 [28]

Explanation:

It is known that formula for area of a sphere is as follows.

A = $4 \pi r^{2}$

= $4 \times 3.14 \times (0.50 m)^{2}$

= 3.14 $m^{2}$

$T_{a}$ = (27 + 273.15) K = 300.15 K

T = (77 + 273.15) K = 350.15 K

Formula to calculate the net charge is as follows.

Q = $esA(T^{4} - T^{4}_{a})$

where, e = emissivity = 0.85

s = stefan-boltzmann constant = $5.6703 \times 10^{-8} Wm^{-2} K^{-4}$

A = surface area

Hence, putting the given values into the above formula as follows.

Q = $esA(T^{4} - T^{4}_{a})$

= $0.85 \times 5.6703 \times 10^{-8} Wm^{-2} K^{-4} \times 3.14 \times ((350.15)^{4} - (300.15)^{4})$

= 1046.63 W

Therefore, we can conclude that the net flow of energy transferred to the environment in 1 second is 1046.63 W.

8 0

3 years ago

Which type of molecule is propanol? <br> A. Alcohol <br> B. Aldehyde <br>C. Ketone <br>D. Amine

snow_lady [41]

Answer:

B.

Explanation:

Propanal is an organic compound with the formula CH3CH2CHO. Aldehyde is colorless, flammable and a slightly fruity odor.

8 0

2 years ago