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3 years ago

What was Johann Dobereiner’s contribution to the development of the periodic table?

Chemistry

2 answers:

Novay_Z [31]3 years ago

5 0

He identified triads of elements that had similar properties

umka21 [38]3 years ago

3 0

he introduced his law of triads. each triad was a group of three elements

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Draw a Lewis structure for ketene, C2H2O , which has a carbon‑carbon double bond. Include all hydrogen atoms and show all unshar

Vladimir79 [104]

Answer: The lewis dot structure is attached below.

Explanation:

A Lewis dot structure is defined as the representation of atoms having electrons around the atom where electrons are represented as dots.

A ketene is an organic compound having general formula R′R″C=C=O, where R and R' are two different/same monovalent chemical groups.

The given chemical compound having formula $C_2H_2O$ is represented as $H_2-C=C=O$ .

Total number of unshared electrons = 4 (left on oxygen atom only)

The lewis dot structure of $C_2H_2O$ is given in the image below.

8 0

3 years ago

What are 5 renewable energy Resources and why are they better for the society and the environment

Ket [755]

Answer:

hydroelectric , hydrogen fuel cells , solar power , geothermal , wind power

Explanation:

all of these has little to no waste being produced and have little to no impact on the environment .

5 0

3 years ago

What kind (ionic or covalent) bond is FeCl2 + Na2CO3? (iron (II) chloride + sodium carbonate).

kipiarov [429]

Answer:

corbonate

Explanation:

i think so. not sure

6 0

3 years ago

(a)-Use Lewis symbol store present there action that occurs between Ca and F atoms. (b)-What is the chemical formula of the most

Charra [1.4K]

Answer:

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

Explanation:

Calcium is the element of second group and forth period. The electronic configuration of Calcium is - 2, 8, 8, 2 or $1s^22s^22p^63s^23p^64s^2$

There are 2 valence electrons of Calcium.

Fluorine is the element of group 17 and second period. The electronic configuration of the element fluorine is - 2, 7 or $1s^22s^22p^5$

There is 1 valence electron of fluorine.

The Lewis structure is drawn in such a way that the octet of each atom is complete.

Thus, calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond. This is done in order that the octet of the atoms are complete and they become stable.

Thus, the formula of calcium chloride is $CaF_2$ .

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

5 0

3 years ago

Different kinds of wood have different densities. The density of american white oak wood is generally 0.77 g/cm3. If Jim grabs a

mixas84 [53]

Answer:

m= 29.645 g

Explanation:

Density:

Density is equal to the mass of substance divided by its volume.

Units:

SI unit of density is Kg/m3.

Other units are given below,

g/cm3, g/mL , kg/L

Formula:

D=m/v

D= density

m=mass

V=volume

Symbol:

The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.

Given data:

density of wood = 0.77 g/cm³

volume= 38.5 cm³

mass= ?

Solution:

d= m/v

m= d × v

m= 0.77 g/cm³× 38.5 cm³

m= 29.645 g

7 0

3 years ago