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2 years ago

Which option correctly describes the pattern of valence electrons on the periodic table? (1 point)

Chemistry

1 answer:

uysha [10]2 years ago

8 0

Answer:

The number of valence electrons increases from left to right.

Explanation: The number of valence electrons increases going across a period, or row in the periodic table, for example, group 1 elements have 1 valence electrons and group 2 elements have have 2.

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Hi what is 100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

kogti [31]

Answer:

2e+130

Explanation:

5 0

3 years ago

Theoretically, what mass of [Co(NH3)4(H2O)2]Cl2 could be produced from 4.00 g of CoCl2•6H2O starting material. If 1.20 g of [Co(

Romashka [77]

<u>Answer:</u> The theoretical yield and percent yield of $[Co(NH_3)_4(H_2O)_2]Cl_2$ is 3.93 g and 30.53 % respectively

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of $CoCl_2.6H_2O$ = 4.00 g

Molar mass of $CoCl_2.6H_2O$ = 238 g/mol

Putting values in equation 1, we get:

$\text{Moles of }CoCl_2.6H_2O=\frac{4.00g}{238g/mol}=0.0168mol$

The chemical equation for the reaction of $CoCl_2.6H_2O$ to form $[Co(NH_3)_4(H_2O)_2]Cl_2$ follows:

$CoCl_2.6H_2O+4NH_3\rightarrow [Co(NH_3)_4(H_2O)_2]Cl_2+4H_2O$

By Stoichiometry of the reaction:

1 mole of $CoCl_2.6H_2O$ produces 1 mole of $[Co(NH_3)_4(H_2O)_2]Cl_2$

So, 0.0168 moles of $CoCl_2.6H_2O$ will produce = $\frac{1}{1}\times 0.0168=0.0168mol$ of $[Co(NH_3)_4(H_2O)_2]Cl_2$

Now, calculating the mass of $[Co(NH_3)_4(H_2O)_2]Cl_2$ from equation 1, we get:

Molar mass of $[Co(NH_3)_4(H_2O)_2]Cl_2$ = 234 g/mol

Moles of $[Co(NH_3)_4(H_2O)_2]Cl_2$ = 0.0168 moles

Putting values in equation 1, we get:

$0.0168mol=\frac{\text{Mass of }[Co(NH_3)_4(H_2O)_2]Cl_2}{234g/mol}\\\\\text{Mass of }[Co(NH_3)_4(H_2O)_2]Cl_2=(0.0168mol\times 234g/mol)=3.93g$

To calculate the percentage yield of $[Co(NH_3)_4(H_2O)_2]Cl_2$ , we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of $[Co(NH_3)_4(H_2O)_2]Cl_2$ = 1.20 g

Theoretical yield of $[Co(NH_3)_4(H_2O)_2]Cl_2$ = 3.93 g

Putting values in above equation, we get:

$\%\text{ yield of }[Co(NH_3)_4(H_2O)_2]Cl_2=\frac{1.20g}{3.93g}\times 100\\\\\% \text{yield of }[Co(NH_3)_4(H_2O)_2]Cl_2=30.53\%$

Hence, the theoretical yield and percent yield of $[Co(NH_3)_4(H_2O)_2]Cl_2$ is 3.93 g and 30.53 % respectively

6 0

2 years ago

The concentration of copper(II) sulfate in one brand of soluble plant fertilizer is 0.070% by weight. If a 21.5 g sample of this

Semmy [17]

Answer:

The molar concentration of $Cu^{2+}$ ions in the given amount of sample is $4.73\times 10^{-5}M$

Explanation:

Given that,

Mass of sample = 21.5 g

0.07 % (m/m) of copper (II) sulfate in plant fertilizer

This means that, in 100 g of plant fertilizer, 0.07 g of copper (II) sulfate is present

So, in 20 g of plant fertilizer

, $=\frac{0.07}{100}\times 21.5}\\=0.0151g$ of copper (II) sulfate is present.

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}$

Mass of solute (copper (II) sulfate) = 0.0151 g

Molar mass of copper (II) sulfate = 159.6 g/mol

Volume of solution = 2.0 L

$\text{Molarity of solution}=\frac{0.0151g}{159.6g/mol\times 2.0L}\\\\\text{Molarity of solution}=4.73\times 10^{-5}M$

The chemical equation for the ionization of copper (II) sulfate follows:

$CuSO_4\rightarrow Cu^{2+}+SO_4^{2-}$

1 mole of copper (II) sulfate produces 1 mole of copper (II) ions and sulfate ions

Molarity of copper (II) ions = $4.73\times 10^{-5}M$

Hence, the molar concentration of $Cu^{2+}$ ions in the given amount of sample is $4.73\times 10^{-5}M$

4 0

3 years ago

The image shows sedimentary rock layers with index

vichka [17]

Layer 2 and layer 9 are the same relative age.

Explanation:

The statement that best describes the rock layers is that Layer 2 and layer 9 are the same relative age..

The relative age is used in placing sedimentary rocks in order of their occurrence.

To do this, we apply the sedimentary laws.

The ones applicable here are:

Principle of superposition states that in an undisturbed sequence, the oldest layer is at the base and youngest on top.
Principle of cross cutting states that a fault and intrusion are younger than the rocks they cut through.
Principle of fossil and fauna succession states that fossils and fauna succeed on another in a determinable form.

We see that layers 2 and 9 have the same fossil and are the same lithological units.

learn more:

Sedimentary rocks brainly.com/question/2740663

#learnwithBrainly

5 0

3 years ago

Salt crystals are shaped like cubes. Salt is part of the _____. isometric crystal system monoclinic crystal system hexagonal cry

sweet [91]

Salt crystals are shaped like cubes. Salt is part of the isometric crystal system.

6 0

3 years ago

Read 2 more answers