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1 year ago

What is a horizontal row of elements on a periodic table

Chemistry

2 answers:

gizmo_the_mogwai [7]1 year ago

8 0

Answer:

periods.

Explanation:

Mariulka [41]1 year ago

3 0

They are called Periods. Lesser known as series

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If a concentration of 10 fluorescent molecules per μm2of cell membrane is needed to visualize a cell under the microscope, how m

lara [203]

Answer : Total molecules that will be needed to visualize a single egg will be 78500 molecules of dye.

Explanation : As a single egg cell has an approximately diameter of 100 μm.

We can use this formula to calculate area of the cell membrane;

A = π $(100)^{2} / 4$ ;

We can take π as 3.14 and we get;

A = 3.14 X $(100)^{2} / 4$

Soving we get;

A = 7850 μ $m^{2}$

Here we have to calculate the amount of dye molecules which will be needed for 10 fluorescent molecules / μ $m^{2}$ but;

here 1 μ $m^{2}$ = 7850 μ $m^{2}$ dye molecules.

Therefore, 10 fluorescent molecules will need;

7850 X 10 = 78500 molecules of dye.

Therefore, the answer is 78500 molecules of dye.

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2 years ago

Draw structures from the following names, and determine which compounds are optically active:(c) 1,2-dibromo-2-methylbutane

dolphi86 [110]

The given compound 1,2-dibromo-2-methylbutane is an optically active compound .

Because this compound does not have plane of symmetry (POS) and center of symmetry (COS) i.e. does not have di-symmetry . And also forms non superimposable mirror image . the compound is optically active .

It has chiral center.

Here , the chiral carbon is attached to the 4 distinct groups such as : methyl , ethyl , bromine , bromomethane .

<h3>What is di-symmetry?</h3>

Di-symmetry is that which have no center of symmetry and plane of symmetry and alternate axis of symmetry .

<h3>Chiral center :</h3>

Have Sp3 hybridized center (4sigma bond ) .

4 distinct group is attached to the chiral atom. form non -superimposable mirror image .

<h3>What is optical isomerism ?</h3>

Same molecular formula and same structural formula . also have same physical and chemical properties .

They differ in their behavior towards plane polarized light (ppl) .

Learn more about chiral center here:

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11 months ago

Which state of matter are particles packed tightly together and fix positions

svet-max [94.6K]

Answer:

Solids.

Explanation:

In a solid object, particles are packed tightly together in fixed positions even if in a container.

7 0

2 years ago

Read 2 more answers

A ball-and-stick model of a molecule of formaldehyde, ch2o, is made from the following components: what do the sticks represent?

9966 [12]

In chemistry, the ball-and-stick model is a molecular ideal of a chemical matter which is to expose both the three-dimensional position of the atoms and the bonds among them. The atoms are normally symbolise by spheres, join by rods which shows the bonds.

Formaldehyde forms formaldehyde structure bond it shares double bond with O2 atoms.

Formaldehyde also known as methanol .

Methanol is colourless.

It is flammable.

It is gas at room temperature.

Methanol having pungent odor and it is a volatile organic compounds.

It is made by the composition of Hydrogen, oxygen, and carbons.

To know more about Formaldehyde here :

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6 0

9 months ago

A 13.1-g sample of CaCl2 is dissolved in 104 g of water, with both substances at 24.7°C. Calculate the final temperature of the

likoan [24]

Answer:

The final temperature of the solution is 44.8 °C

Explanation:

assuming no heat loss to the surroundings, all the heat of solution (due to the dissolving process) is absorbed by the same solution and therefore:

Q dis + Q sol = 0

Using tables , can be found that the heat of solution of CaCl2 at 25°C (≈24.7 °C) is q dis= -83.3 KJ/mol . And the molecular weight is

M = 1*40 g/mol + 2* 35.45 g/mol = 110.9 g/mol

Q dis = q dis * n = q dis * m/M = -83.3 KJ/mol * 13.1 g/110.9 gr/mol = -9.84 KJ

Qdis= -9.84 KJ

Also Qsol = ms * Cs * (T - Ti)

therefore

ms * Cs * (T - Ti) + Qdis = 0

T= Ti - Qdis * (ms * Cs )^-1 =24.7 °C - (-9.84 KJ/mol)/[(104 g + 13.1 g)* 4.18 J/g°C] *1000 J/KJ

T= 44.8 °C

7 0

3 years ago