All categories

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....

You might be interested in

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

3 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