What happens to electrons in the photoelectric effect?

High concentrations of ammonia (NH3), nitrite ion, and nitrate ion in water can kill fish. Lethal concentrations of these specie

kykrilka [37]

Explanation:

It is known that molality is the number of moles present in kg of solution.

Mathematically, Molality = $\frac{\text{no. of moles of solute}}{\text{mass of solvent in Kg}}$

The given data is as follows.

Molar mass of ammonia = 17 g/mol

Concentration = 1.002 mg/L = $\frac{0.001002 g/L}{17 g/mol}$

= $5.89 \times 10^{-4}$ mol/L

Also, density = $\frac{1 g}{mL}$ = 1 kg/L

Therefore, molality will be calculated as follows.

Molality = $\frac{5.89 \times 10^{-4} mol/L}{1 kg/L}$

= $5.89 \times 10^{-4} mol/kg$

And,

Molar mass of nitrite = 46 g/mol

Concentration = 0.387 mg/L = $\frac{0.000412 g/L}{46 g/mol}$

= $8.956 \times 10^{-6}$ mol/L

And, density = $\frac{1 g}{mL}$ = 1 kg/L

Hence, molality = $\frac{8.956 \times 10^{-6} mol/L}{1 kg/L}$

= $8.956 \times 10^{-6}$ mol/kg

Now, Molar mass of nitarte = 62 g/mol

Concentration = 1352.2 mg/L

= $\frac{1.3522 g/L}{62 g/mol}$

= 0.02181 mol/L

Also, density = $\frac{1 g}{mL}$ = 1 kg/L

Hence, molality will be calculated as follows.

Molality = $\frac{0.02181 mol/L}{1 kg/L}$

= 0.02181 mol/kg

Therefore, molality of given species is $5.89 \times 10^{-4} mol/kg$ for ammonia, $8.956 \times 10^{-6}$ mol/kg for nitrite, and 0.02181 mol/kg for nitrate ion.

7 0

3 years ago

A 100 W light bulb is placed in a cylinder equipped with a moveable piston. The light bulb is turned on for 2.0×10−2 hour, and t

drek231 [11]

Answer:

(a) ΔU = 7.2x10²

(b) W = -5.1x10²

(c) q = 5.2x10²

Explanation:

From the definition of power (p), we have:

$p = \frac {\Delta W}{\Delta t} = \frac {\Delta U}{\Delta t}$ (1)

where, p: is power (J/s = W (watt)) W: is work = ΔU (J) and t: is time (s)

(a) We can calculate the energy (ΔU) using equation (1):

$\Delta U = p \cdot \Delta t = 100 \frac{J}{s} \cdot 2.0\cdot 10^{-2} h \cdot \frac{3600s}{1h} = 7.2 \cdot 10^{2} J$

(b) The work is related to pressure and volume by:

$\Delta W = -p \Delta V$

where p: pressure and ΔV: change in volume = V final - V initial

$\Delta W = - p \cdot (V_{fin} - V_{ini}) = - 1.0 atm (5.88L - 0.85L) = - 5.03 L \cdot atm \cdot \frac{101.33J}{1 L\cdot atm} = -5.1 \cdot 10^{2} J$

(c) By the definition of Energy, we can calculate q:

$\Delta U = \Delta W + \Delta q$

where Δq: is the heat transfer

$\Delta q = \Delta U - \Delta W = 7.2 J - (-5.1 \cdot 10^{2} J) = 5.2 \cdot 10^{2} J$

I hope it helps you!

6 0

3 years ago

Put the list in chronological order (1–5).

Leokris [45]

Explanation:

Filtration is a separation technique in which solid particles suspended in liquid medium are separated by allowing the mixture through the pores of the filter paper. By this solid particles get collect on filter paper and liquid drains out from the pores of the filter paper.

The chronological order for given steps will be:

Weigh and fold the filter paper.
Place the filter paper in the funnel, then place the funnel in the Erlenmeyer flask.
Allow the solid/liquid mixture to drain through the filter.
Use water to rinse the filter paper containing the mixture.
Weigh the dried filter paper and copper.

4 0

3 years ago

Read 2 more answers

Metric prefix name for 1/100 ?

babymother [125]

The metric prefix name for 1/100 is centimeters.

5 0

3 years ago

Yeast and other organisms can convert glucose (C6H12O6) to ethanol (CH3CH2OH) by a process called alchoholic fermentation. The n

NISA [10]

Answer:

8.37 grams

Explanation:

The balanced chemical equation is:

C₆H₁₂O₆ ⇒ 2 C₂H₅OH (l) + 2 CO₂ (g)

Now we are asked to calculate the mass of glucose required to produce 2.25 L CO₂ at 1atm and 295 K.

From the ideal gas law we can determine the number of moles that the 2.25 L represent.

From there we will use the stoichiometry of the reaction to determine the moles of glucose which knowing the molar mass can be converted to mass.

PV = nRT ⇒ n = PV/RT

n= 1 atm x 2.25 L / ( 0.08205 Latm/kmol x 295 K ) =0.093 mol CO₂

Moles glucose required:

0.093 mol CO₂ x ( 1 mol C₆H₁₂O₆ / 2 mol CO₂ ) = 0.046 mol C₆H₁₂O₆

The molar mass of glucose is 180.16 g/mol, then the mass required is

0.046 mol x 180.16 g/mol = 8.37 g

5 0

3 years ago