The proportion of dissolved substances in seawater is usually expressed in

KNO3(s) --> K+(aq) + NO3-(aq)This reaction was carried out in a Styrofoam insulated calorimeter and the following data were r

nataly862011 [7]

Answer:

Equation correctly showing the heat of solution

$KNO_3(s)+35.2 kJ \rightarrow K^+(aq) + NO_{3}^-(aq)$

Explanation:

Mass of aqueous solution = m = 100 g

Specific heat of solution = c = 4.18 J/gºC

Change in temperature = $\Delta T=T_f-T_i$

ΔT = 21.6ºC - 30.0ºC = -8.4ºC

Heat lost by the solution = Q

$Q = mc\Delta T$

$Q=100 g\times 4.18 J/g^oC\times (-8.4^oC)$

Q = -3,511.2 J ≈ -3.51 kJ

Heat absorbed by potassium nitrate when solution in formed; Q'

Q' = -Q = 3.51 kJ

Moles of potassium nitrate , n= $\frac{10.1 g}{101 g/mol}=0.1 mol$

$KNO_3(s)\rightarrow K^+(aq) + NO_{3}^-(aq)$

The heat of solution =

$\frac{Q'}{n}=\frac{3.5112 kJ}{0.1 mol}=35.1 kJ/mol$

So, the equation correctly showing the heat of solution

$KNO_3(s)+35.2 kJ \rightarrow K^+(aq) + NO_{3}^-(aq)$

4 0

4 years ago

Convert 4.500000000 to scientific notation

aniked [119]

I think it’s 4.5 x 10^9

7 0

4 years ago

I need help with this pls i don’t understand it

FromTheMoon [43]

Answer:

Inner core - A

Outer core - B

Mantle - C

Asthenosphere - F

Lithosphere - E

Crust - D

7 0

1 year ago

Given that the density of TlCl(s) is 7.00 g/cm3 and that the length of an edge of a unit cell is 385 pm, determine how many form

ryzh [129]

Here's my best guess
the volume of the unit cell is (385*10^-12)^3=5.7066*10^-29 m^3
multiply by density to get mass mass = (7 g/cm^3)*(100^3 cm^3 / 1^3 m^3) * 5.7066*10^-29 m^3= 3.99466*10^-22 g
covert to moles 3.99466*10^-22 g * 1 mol / 239.82 g = 1.6657 *10^-24 mol
convert to number of units

1.6657 *10^-24 mol * 6.23*10^23 units/mol = 1.04

385 pm = 3.85*10^(-8) cm

The volume of the unit cell is the cube of that, which is 5.71*10^(-23) cm^3. Since the ratio of mass to volume (i.e. the density) must be the same no matter what amount of TlCl you have, you can say:
7 = x/(5.71*10^(-23)), where x is the mass of the unit cell. Solving for x, you get 4*10^(-22) g.

The mass of a molecule of TlCl is 240 amu, which in grams is 4*10^(-22) g. The mass of the unit cell and the mass of a molecule of TlCl is the same. Therefore there is one formula unit of TlCl per unit cell.

3 0

4 years ago

Sodium chlorate, NaClO3, decomposes when heated to yield sodium chloride and oxygen, a reaction used to provide oxygen for the e

netineya [11]

Sodium chlorate decomposes into sodium chloride and oxygen.
The reaction is
NaClO3 --Δ--> NaCl + O2
The Δ means that heat is used
This equation is still not balanced.
Balancing the equation
2NaClO3 --Δ--> 2NaCl + 3O2
The equation is now balanced.

3 0

3 years ago