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3 years ago

How is a double displacement reaction completed and balanced

1 answer:

7 0

A double displacement reaction is a type of reaction in which two reactants exchange ions to form two new compounds. Many double displacement reactions occur between ionic compounds that are dissolved in water. A double replacement reaction is represented by the general equation.

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Why does waters boiling point decrease with increases in elevation

lesantik [10]

Answer:

Waters' boiling point decreases with increases in elevation because of the atmospheric pressure.

For example, the higher in elevation you are. The lower the atmospheric pressure is. In other words heated water reached boiling point quicker.

3 0

3 years ago

Read 2 more answers

How many moles of potassium hydroxide are needed to completely react with 2.94 moles of aluminum sulfate

ArbitrLikvidat [17]

Answer:- Third choice is correct, 17.6 moles

Solution:- The given balanced equation is:

Al_2(SO_4)_3+6KOH\rightarrow 2Al(OH)_3+3K_2SO_4

We are asked to calculate the moles of potassium hydroxide needed to completely react with 2.94 moles of aluminium sulfate.

From the balanced equation, there is 1:6 mol ratio between aluminium sulfate and potassium hydroxide.

It is a simple mole to mole conversion problem. We solve it using dimensional set up as:

2.94molAl_2(SO_4)_3(\frac{6molKOH}{1molAl_2(SO_4)_3})

= 17.6 mol KOH

So, Third choice is correct, 17.6 moles of potassium hydroxide are required to react with 2.94 moles of aluminium sulfate.

6 0

3 years ago

In the laboratory a student determines the specific heat of a metal. She heats 19.6 grams of zinc to 98.37°C and then drops it i

fgiga [73]

Answer:

The specific heat of zinc is 0.375 J/g°C

Explanation:

<u>Step 1:</u> Data given

Mass of zinc = 19.6 grams

Mass of water = 82.9 grams

Initial temperature of zinc = 98.37 °C

Initial temperature of water = 24.16 °C

Final temperature of water (and zinc) = 25.70 °C

Specific heat of water = 4.184 J/g°C

<u>Step 2:</u> Calculate Specific heat of zinc

Heat lost by zinc = heat won by water

Q=m*c*ΔT

Qzinc = -Qwater

m(zinc)*C(zinc)*ΔT(zinc) = -m(water)*C(water)*ΔT(water)

⇒ with mass of zinc = 19.6 grams

⇒ with C(zinc) = TO BE DETERMINED

⇒ with ΔT(zinc) = T2 -T1 = 25.70 - 98.37 = -72.67°C

⇒ with mass of water = 82.9 grams

⇒ with C(water) = 4.184 J/g°C

⇒ with ΔT(water) = T2 - T1 = 25.70 - 24.16 = 1.54

Qzinc = -Qwater

19.6g* C(zinc) * (-72.67°C) = - 82.9g* 4.184 J/g°C * 1.54 °C

-1424.332*C(zinc) = -534.155

C(zinc) = 0.375 J/g°C

The specific heat of zinc is 0.375 J/g°C

7 0

3 years ago

28. After 3 substances are mixed, an odor emits

Lyrx [107]

Answer:

a. chemical change

Explanation:

A chemical change can cause an odor, however a physical change cannot, and the use of thermal energy will only make an object colder, not give it an odor.

7 0

3 years ago

Read 2 more answers

Be sure to answer all parts. Plutonium−242 decays to uranium−238 by emission of an α particle with an energy of 4.853 MeV. The 2

zheka24 [161]

Answer:

(a)²⁴²₉₄Pu ⇒ ⁴₂He + ²³⁸₉₂U ⇒ ²³⁸₉₂U + ⁰₀γ

(b) 4.898 MeV

Explanation:

In the nuclear reaction, it was stated that plutonium-242 decayed firstly to uranium-238 and alpha, and lastly to a stable uranium-238 by emitting a gamma ray. The balanced equation for the nuclear reactions is shown below:

(a)²⁴²₉₄Pu ⇒ ⁴₂He + ²³⁸₉₂U ⇒ ²³⁸₉₂U + ⁰₀γ

(b) The energy emitted by releasing a gamma ray is calculated using:

E = hc/λ

where

h = 4.136*10^-15 eV.s

c = 299792458 m/s

λ = 0.02757 nm = 0.02757*10^-9 m

Therefore:

E = (4.136*10^-15)*(299792458)/0.02757*10^-9 = 44974.31 eV

The total energy if the stable 238U was produced directly would be

4.853*10^6 + 44974.31 = 4.898 MeV

4 0

4 years ago