What is another name for a column of elements

Which best describes the effect of j.j. thompsons theory

dangina [55]

The accepted model of the atom was changed.

8 0

3 years ago

What effect do calcium ions have on the water in ecosystems?

Marysya12 [62]

It's because they add to its hardness . Calcium is naturally dissolved in water

6 0

3 years ago

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The gas SF6 is used to trace air flows because it is non-toxic and can be detected selectively in air at a concentration of 1.0

melomori [17]

SF₆ in the air at a concentration of 1.0 ppb, exerts a partial pressure of 1.0 × 10⁻⁹ atm. At this concentration, 2.3 × 10¹⁰ molecules of SF₆ are contained in 1.0 cm³ of air at 46 °C.

First, we will calculate the partial pressure of SF₆ using the following expression.

$pSF_6 = P \times \frac{ppb}{10^{9} }$

where,

pSF₆: partial pressure of SF₆

P: total pressure of air (we will assume it is 1 atm)

ppb: concentration of SF₆ in parts per billion

$pSF_6 = P \times \frac{ppb}{10^{9} } = 1 atm \times \frac{1.0 ppb}{10^{9} } = 1.0 \times 10^{-9} atm$

Then, we will convert 1.0 cm³ to L using the following conversion factors:

1 cm³ = 1 mL
1 L = 1000 mL

$1.0 cm^{3} \times \frac{1mL}{1cm^{3}} \times \frac{1L}{1000 mL} = 1.0 \times 10^{-3} L$

Next, we will convert 46 °C to Kelvin using the following expression.

$K = \° C + 273.15 = 46 + 273.15 = 319 K$

Afterward, we calculate the moles (n) of sulfur hexafluoride using the ideal gas equation.

$P \times V = n \times R \times T\\n = \frac{P \times V}{R \times T} = \frac{1.0 \times 10^{-9} atm \times 1.0 \times 10^{-3} L}{(0.082 atm.L/mol.K) \times 319 K} = 3.8 \times 10^{-14} mol$

Finally, we will convert 3.8 × 10⁻¹⁴ mol to molecules using Avogadro's number.

$3.8 \times 10^{-14} mol \times \frac{6.02 \times 10^{23} molecules }{mol} = 2.3 \times 10^{10} molecules$

SF₆ in the air at a concentration of 1.0 ppb, exerts a partial pressure of 1.0 × 10⁻⁹ atm. At this concentration, 2.3 × 10¹⁰ molecules of SF₆ are contained in 1.0 cm³ of air at 46 °C.

You can learn more about partial pressure here: brainly.com/question/13199169

6 0

3 years ago

Write the net cell equation for this electrochemical cell. Phases are optional. Do not include the concentrations. Co ( s ) ∣ ∣

Tatiana [17]

Answer: The overall equation will be $Co(s)+2Ag^+(aq)\rightarrow Co^{2+}(aq)+Ag(s)$

Explanation:

The representation is given by writing the anode on left hand side followed by its ion with its molar concentration. It is followed by a salt bridge. Then the cathodic ion with its molar concentration is written and then the cathode.

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.

Anode : $Co(s)\rightarrow Co^{2+}(aq)+2e^{-}$

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

Cathode : $Ag^+(aq)+e^{-1}\rightarrow Ag(s)$ $\times 2$

The number of electrons lost must be equal to the number of electrons gained , thus overall equation will be :

$Co(s)+2Ag^+(aq)\rightarrow Co^{2+}(aq)+Ag(s)$

5 0

2 years ago

The intake stroke of a positive displacement compressor is most similar to that of a

umka21 [38]

Answer:

D. two-stroke cylinder engine.

Explanation:

Two-stroke cylinder engine: In chemistry, the term "two-stroke cylinder engine" is described as one of the types of "internal combustion engine" that tends to complete a single "power cycle" possessing two different strokes of the "piston" during a particular "crankshaft revolution".

It generally consists of two different strokes that are being often known as power or exhaust and suction stroke.

In the question above, the given statement signifies the "two-stroke cylinder engine". 

5 0

3 years ago