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3 years ago

How does the number of valence electrons in an atom relate to the elements placement on the periodic table?

1 answer:

8 0

If the number of valence electron is one than it will be placed in group IA. elements of group IIA will have two valence electrons and so on....

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The accepted value for the molar volume of a gas is 22.4 L. Sarah's experimental data indicated that a mole of a gas had a volum

Amanda [17]

Answer:

Percent error = 12.5%

Explanation:

In a measurement you can find percent error following the formula:

Percent error = |Measured value - Accepted Value| / Acepted value * 100

Based on the data of the problem, accepted value is 22.4L and the measured Value (Value of Sara) was 19.6L.

Replacing:

Percent error = |Measured value - Accepted Value| / Acepted value * 100

Percent error = |19.6L - 22.4L| / 22.4L * 100

Percent error = |-2.8L| / 22.4L * 100

Percent error = 2.8L / 22.4L * 100

Percent error = 12.5%

3 0

2 years ago

1. (8pt) Using dimensional analysis convert 600.0 calories into kilojoules

Ivanshal [37]

Answer:

1. 2.510kJ

2. Q = 1.5 kJ

Explanation:

Hello there!

In this case, according to the given information for this calorimetry problem, we can proceed as follows:

1. Here, we consider the following equivalence statement for converting from calories to joules and from joules to kilojoules:

$1cal=4.184J\\\\1kJ=1000J$

Then, we perform the conversion as follows:

$600.0cal*\frac{4.184J}{1cal}*\frac{1kJ}{1000J}=2.510kJ$

2. Here, we use the general heat equation:

$Q=mC(T_2-T_1)$

And we plug in the given mass, specific heat and initial and final temperature to obtain:

$Q=236g*0.24\frac{J}{g\°C} (34.9\°C-8.5\°C)\\\\Q=1495.3J*\frac{1kJ}{1000J} \\\\Q=1.5kJ$

Regards!

7 0

2 years ago

Which of the following is a major difference between elliptical galaxies and spiral galaxies?

SashulF [63]

Its A because I did it on connexus

5 0

3 years ago

A 0.0000792 M sample of Compound X in a solvent has an absorbance of 0.341 at 528 nm in a 1.000-cm cuvet. The solvent alone has

natima [27]

Answer:

a) a = 3485 M⁻¹cm⁻¹

b) C = 0,000127 M

Explanation:

Lambert-Beer law says that there is a linear relationship between absorbance and concentration of a chemical substance. The formula is:

A = a×b×C

Where A is absorbance, a is molar absorptivity, b is path length and C is concentration.

a) In the problem Concentration is 0.0000792 M, b is 1,000cm and Absorbance is absorbance of sample-absorbance of blank: 0,341-0,065 = 0,276

Replacing:

0,276 = a×1,000cm×0,0000792M

a = 3485 M⁻¹cm⁻¹

b) As the experiment consist in the same compound in the same solvent, the molar absorptivity will be the same, a = 3485 M⁻¹cm⁻¹, path length will be 1,000cm and absorbance: 0,508-0,065 = 0,443

Replacing:

0,443 = 3485 M⁻¹cm⁻¹×1,000cm×C

C = 0,000127 M

I hope it helps!

8 0

2 years ago

The town of Natrium, West Virginia, derives its name from the sodium produced in the electrolysis of molten sodium chloride (NaC

Alona [7]

Explanation:

The reaction equation will be as follows.

$Na^{+} + e^{-} \rightarrow Na(s)$

Hence, moles of Na = moles of electron used

Therefore, calculate the number of moles of sodium as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{4500 g}{23 g/mol}$ (as 1 kg = 1000 g)

= 195.65 mol

As, Q = $n \times F$ where F = Faraday's constant

= $195.65 mol \times 96500 C$

= $1.88 \times 10^{7}$ mol C

Relation between electrical energy and Q is as follows.

E = $Q \times V$

Hence, putting the given values into the above formula and then calculate the value of electricity as follows.

E = $Q \times V$

= $1.88 \times 10^{7} \times 5$

= $9.4 \times 10^{7} J$

As 1 J = $2.77 \times 10^{-7}$ kWh

Hence, $\frac{9.4 \times 10^{7}}{2.77 \times 10^{-7}}$ kWh

= 3.39 kWh

Thus, we can conclude that 3.39 kilowatt-hours of electricity is required in the given situation.

7 0

3 years ago

Read 2 more answers