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3 years ago

Which of the following is NOT a qualitative observation

Chemistry

1 answer:

frozen [14]3 years ago

4 0

what is the following???

a qualitative observation is when somehthings appearance changes like form red to blue, and qualitative is when the umber of something changes.

Hope this helps

Kenny

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The image below shows a laser that has been shot into a solid block of transparent plastic from the far left end. Once inside th

OlgaM077 [116]

Answer:

A. Optical fibers transmit light signals in high-speed communications.

Explanation:

You didn't include the image, but it probably showed light bouncing off the sides as in the diagram below.

It demonstrates how optical fibers transmit light signals in high-speed communications.

B is wrong. Satellites communicate by radio waves.

C is wrong. Solar cells convert light energy to

D is wrong. Power plants transmit electrical energy to homes through copper wires.

7 0

4 years ago

4NH3 + 502 --> 4NO + 6H20

gregori [183]

Answer:

5.52 g

Explanation:

4NH₃ + 5O₂ → 4NO + 6H₂O

First we convert the given masses of both reactants into moles, using their respective molar masses:

6.30 g NH₃ ÷ 17 g/mol = 0.370 mol NH₃

1.80 g O₂ ÷ 32 g/mol = 0.056 mol O₂

Now we calculate with how many NH₃ moles would 0.056 O₂ moles react, using the stoichiometric coefficients:

0.056 mol O₂ * $\frac{4molNH_3}{5molO_2}$ = 0.045 mol NH₃

As there more NH₃ moles than required, NH₃ is the excess reactant.

Then we calculate how many NH₃ moles remained without reacting:

0.370 mol NH₃ - 0.045 mol NH₃ = 0.325 mol NH₃

Finally we convert NH₃ moles into grams:

0.325 mol NH₃ * 17 g/mol = 5.52 g

7 0

3 years ago

You are given an aqueous solution and are asked to analyze it for the presence (or absence) of Ag+(aq), Ca2+(aq), and/or Hg2+(aq

pantera1 [17]

Answer:

Explanation:

In the first step, hydrochloric acid (HCl) is added to the solution. In this case the equilibrium that could take place is:

Ag⁺(aq) + Cl⁻(aq) ↔ AgCl(s)

But no precipitate was formed, so Ag⁺(aq) is absent.

By adding H₂SO₄(aq) the next equilibrium that could take place is:

Ca⁺²(aq) + SO₄⁻²(aq) ↔ CaSO₄(s)

A white precipitate was formed, so Ca⁺² is present in the solution.

The following could take place after adding H₂S(aq):

Hg²⁺(aq) + S⁻² ↔ HgS(s)

A black precipitate formed, so Hg⁺² is present as well.

6 0

3 years ago

If 4520 kj of heat is needed to boil a sample of water, what is the mass of water

Cerrena [4.2K]

Answer:

1,085g of water

Explanation:

If we have the value 4520kj is because the question is related to Energy and heat capacity. In this case, the law and equation that we use is the following:

Q= m*C*Δt where;

Q in the heat, in this case: 4520kj

m is the mas

Δt= is the difference between final-initial temperature (change of temperature), in this exercise we don´t have temperatura change.

In order to determine the mass, I will have the same equation but finding m

m= Q/C*Δt without m=Q/C

So: m= 4,520J/4.18J/g°C

m= 1,0813 g

5 0

3 years ago

Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the following equation:

rusak2 [61]

Answer:

60.42% is the percent yield of the reaction.

Explanation:

Moles of methane gas at 734 Torr and a temperature of 25 °C.

Volume of methane gas = V = 26.0 L

Pressure of the methane gas = P = 734 Torr = 0.9542 atm

Temperature of the methane gas = T = 25 °C = 298.15 K

Moles of methane gas = n

$PV=nRT$

$n=\frac{PV}{RT}=\frac{0.9542 atm\times 26.0L}{0.0821 atm L/mol K\times 298.15 K}=1.0135 mol$

Moles of water vapors at 700 Torr and a temperature of 125 °C.

Volume of water vapor = V' = 23.0 L

Pressure of water vapor = P' = 700 Torr = 0.9100 atm

Temperature of water vapor = T' = 125 °C = 398.15 K

Moles of water vapor gas = n'

$P'V'=n'RT'$

$n'=\frac{PV}{RT}=\frac{0.9100 atm\times 23.0L}{0.0821 atm L/mol K\times 398.15 K}=0.6402 mol$

$CH_4(g)+H_2O(g)\rightarrow CO(g)+3H_2(g)$

According to reaction , 1 mol of methane reacts with 1 mol of water vapor. As we can see that moles of water vapors are in lessor amount which means it is a limiting reagent and formation of hydrogen gas will depend upon moles of water vapors.

According to reaction 1 mol of water vapor gives 3 moles of hydrogen gas.

Then 0.6402 moles of water vapor will give:

$\frac{3}{1}\times 0.6402 mol=1.9208 mol$ of hydrogen gas