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weeeeeb [17]
2 years ago
6

George is writing a newspaper article about the fire at the local library. His introductory paragraph has an example of conserva

tion of mass. Underline the sentence that illustrates conservation of mass.
A. Our town library dealt with a terrible fire in one of its rooms over the weekend

B. Firefighters rushed to the scene, but were too late.

C. The room contained much-loved books and magazines

D. The mayor arrived soon afterward and urged everyone to donate to help rebuild this important community building

E. All that remained of the books and magazines were ash, water vapor, and carbon dioxide fumes
Chemistry
2 answers:
Lina20 [59]2 years ago
7 0

Answer:

D

Explanation:

zmey [24]2 years ago
3 0

Answer:

D

Explanation:

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Predict the initial and isolated products for the reaction. The starting material is a 6 carbon chain where there is a triple bo
satela [25.4K]

Answer:

See explanation and image attached

Explanation:

This reaction is known as mercuric ion catalyzed hydration of alkynes.

The first step in the reaction is attack of the mercuric ion on the carbon-carbon triple bond, a bridged intermediate is formed. This bridged intermediate is attacked by water molecule to give an organomercury enol. This undergoes keto-enol tautomerism, proton transfer to the keto group yields an oxonium ion, loss of the mercuric ion now gives equilibrium keto and enol forms of the compound. The keto form is favoured over the enol form.

7 0
2 years ago
The standard reduction potentials for two half-cells involving iron are: given below. Fe2+ (aq) + 2e– ® Fe (s) Eο = –0.44 V Fe3+
matrenka [14]

Answer:

Explanation:

Fe⁺² (aq) + 2e⁻ =   Fe (s)   ;   E⁰ =  - .44 V

Fe⁺³ (aq) + e⁻ =  ® Fe²⁺ (aq) ;   E⁰ = + .77 V

Reduction potential of second reaction is more , so it will take place , ie Fe⁺³ will be reduced and Fe will be oxidised .

So reaction in the combined cell will be

2Fe⁺³ + Fe = 3Fe⁺²

cell potential = .77 - ( - .44 )

= 1.21 V .

6 0
2 years ago
A 2400.-gram sample of an aqueous solution contains 0.012 gram of nh3. What is the concentration of nh3 in the solution
Kryger [21]

Answer : The concentration of NH_3 in the solution is, 2.94\times 10^{-4}M

Explanation :

First we have to calculate the volume of aqueous solution that is water.

Density of water = 1.00 g/mL

Mass of water = 2400 g

\text{Volume of water}=\frac{Mass}{Density}=\frac{2400g}{1.00g/mL}=2400mL

Now we have to calculate the concentration of ammonia solution.

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

\text{Molarity}=\frac{\text{Mass of }NH_3\times 1000}{\text{Molar mass of }NH_3\times \text{Volume of solution (in mL)}}

Molar mass of NH_3 = 17 g/mole

Now put all the given values in this formula, we get:

\text{Molarity}=\frac{0.012g\times 1000}{17g/mole\times 2400mL}=3.12mole/L=2.94\times 10^{-4}M

Therefore, the concentration of NH_3 in the solution is, 2.94\times 10^{-4}M

7 0
2 years ago
1. A student performs a reaction in a beaker by reaction silver nitrate with one long copper wire. The student’s thermometer cha
stiv31 [10]

Explanation:

The observation of student was that thermometer reading changed from 27°C to 35°C which indicates that temperature of the beaker solution rose after reaction due to release of heat during reaction as a product.

Those chemical reactions which gives heat energy as a product into their surrounding are categorized as exothermic reactions. During the course of these reaction temperature of the surroundings also increased.

So, this means that reaction between silver nitrate and copper wire is an exothermic reaction.

Three ways that the student could speed up the reaction :

  • By adding catalyst to the reaction.
  • By decreasing the temperature.
  • By increasing the concentration of silver nitarte solution.
3 0
2 years ago
Read 2 more answers
What is the total E associated with one mole of photons (a unit known as the Einstein) of 3.91x1019 Hz?
sashaice [31]

Answer:

        E=1.56\times 10^{10}J

Explanation:

The<em> energy of a photon</em>, E, can be calculated with the Planck-Einstein equation:

          E=hf

Where:

  • h is Planck's constant 6.626×10⁻³⁴ J.s, and
  • f is the frequency of the photon or electromagnetic radiation.

Substituting with your data:

          E=6.626\times 10^{-34}J.s\times 3.91\times 10^{19}s^{-1}=2.5908\times 10^{-14}J

Now multiply by Avogadro's number to obtain the energy of one mole of photons:

          E=2.5908\times 10^{-14}J\times 6.022\times 10^{23}=1.56\times 10^{10}J

8 0
1 year ago
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