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3 years ago

10

HELP ASAP Choose three sections of the electromagnetic spectrum. Rank them in order of energy. Give an example of how they are u

sed for each.

1 answer:

hodyreva [135]3 years ago

4 0

Isn’t Bambi undo hall

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What does it mean that something is a conservative ion?

mario62 [17]

Answer:

The major ionic constituents whose concentrations can be determined from the salinity are known as conservative substances. Their constant relative concentrations are due to the large amounts of these species in the oceans in comparison t

5 0

3 years ago

30 POINTS! ----- How many moles of oxygen gas are needed to completely react with 145 grams of aluminum? Report your answer with

gladu [14]

First a balanced reaction equation must be established:
$4Al _{(s)} + 3 O_{2} _{(g)}$ → $2 Al_{2} O_{3}$

Now if mass of aluminum = 145 g
the moles of aluminum = (MASS) ÷ (MOLAR MASS) = 145 g ÷ 30 g/mol
= 4.83 mols

Now the mole ratio of Al : O₂ based on the equation is 4 : 3
[4Al + 3 O₂ → 2 Al₂O₃]

∴ if moles of Al = 4.83 moles
then moles of O₂ = (4.83 mol ÷ 4) × 3
= 3.63 mol (to 2 sig. fig.)

Thus it can be concluded that 3.63 moles of oxygen is needed to react completely with 145 g of aluminum.

4 0

4 years ago

A fluorine atom has 9 positive charge,9 negative charges and a mass of 19. Describe the structure of its atom.

Tanya [424]

The atomic structure of the atom contains 9 positively charged particles (protons) and 10 neutrally charged particles (neutrons) in the center of the atom in a clump called the nucleus. Those 9 negatively charged particles (electrons) are moving around outside of the nucleus.
There are 10 neutral charges, because the mass of 19 comes from the number of neutral charges plus the number of positive charges.
To calculate the number of neutral charges, subtract the positive charges from the mass (19 - 9), and you get the number of neutral charges (10).

6 0

3 years ago

Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 8.60 MJ o

Alecsey [184]

Answer: $64.216\times 10^4grams$ of liquid sodium is required.

Explanation: To calculate the mass of liquid sodium, we use the formula:

$q=nc\Delta T\\q=\frac{m}{M}c\Delta T$

where,

q = heat required, $8.60MJ=8.60\times 10^6J$ (Conversion factor: 1MJ = 1000000J)

m = Mass of liquid sodium, $?g$

M = Molar mass of liquid sodium, $23g/mol$

c = Specific heat capacity, $30.8J/Kmol$

$\Delta T$ = change in temperature, $\Delta T=(510-500)K=10K$ (Conversion factor: 0°C = 273K)

Putting values in above equation, we get:

$8.60\times 10^6J=\frac{m}{23g/mol}\times 30.8J/Kmol\times 10K$

$m=64.216\times 10^4grams$

5 0

3 years ago

For the reaction below, Kp 5 1.16 at 800.8C. CaCO3(s) 34 CaO(s) 1 CO2(g) If a 20.0-g sample of CaCO3 is put into a 10.0-L contai

Elena L [17]

Answer:

The mass percentage of calcium carbonated reacted is 2.5%.

Explanation:

The reaction is:

$CaCO_{3}(s)--->CaO(s)+CO_{2}(g)$

Thus the Kp of the equilibrium will be:

Kp = partial pressure of carbon dioxide [as the other are solid]

Moles of calcium carbonate initially present = $\frac{mass}{molarmass}=\frac{20}{100}=0.2$

Let us apply ICE table to the equilibrium given:

$CaCO_{3}(s)--->CaO(s)+CO_{2}(g)$

Initial 0.2 0 0

Change -x +x +x

Equilibrium 0.2-x x x

Kp = partial pressure of carbon dioxide

Kp = Kc(RT)ⁿ

where n = difference in the number of moles of gaseous products and reactants

for given reaction n = 1

R = gas constant = 8.314 J /mol K

T = temperature = 800 ⁰C = 1073 K

Putting values

Kc = $\frac{Kp}{RT}=\frac{1.16}{8.314X1073}=1.3X10^{-4}$

Kc = $\frac{[CO_{2}][CaO]}{[CaCO_{3}]}= \frac{x^{2} }{(0.2-x)}=1.3X10^{-4}$

$1.3X10^{-4}(0.2-x)=x^{2}$

$x^{2} = 0.26X10^{-4}-1.3X10^{-4}x$

On calculating

x = 0.005

where x = the moles of calcium carbonate dissociated or reacted.

Percentage of the moles or mass reacted = $\frac{molesreacted X100}{initialmoles}=\frac{0.005X100}{0.2}=2.5$ %

7 0

3 years ago