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Natalka [10]
2 years ago
7

Which metal in Period 5 is very reactive and has two valence electrons in each atom?

Chemistry
2 answers:
Contact [7]2 years ago
6 0

Answer:

The right answer is A, that is Rubidium (Rb)

Explanation:

Strontium has 2 electrons in the valance shell and is alkaline earth metal but relatively reactive.

Rubidium comes in period 5 and under alkali metals and very reactive towards oxygen and highly reactive than strontium  and other option

This element has 2 electrons in its valence subshell (5s) according to Madelung rule.

Madelung rule that if the two orbitals have the same n+l value they fill in increasing order of n.

So the right answer is A, that is Rubidium (Rb)

Aleks04 [339]2 years ago
6 0

Answer: B. strontium (Sr)

Explanation:

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Answer: 2.8

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dsp73

Answer: 1. 2Al+3CuCl_2\rightarrow 2AlCl_3+3Cu

2. 3 moles of CuCl_2 : 2 moles of Al

3. 0.33 moles of CuCl_2 : 0.92 moles of Al

4. CuCl_2 is the limiting reagent and Al is the excess reagent.

5. Theoretical yield of AlCl_3 is 29.3 g

Explanation:

To calculate the moles :

\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}    

\text{Moles of} Al=\frac{25.0g}{27g/mol}=0.92moles

\text{Moles of} CuCl_2=\frac{45.0g}{134g/mol}=0.33moles

The balanced chemical equation is:

2Al+3CuCl_2\rightarrow 2AlCl_3+3Cu  

According to stoichiometry :

3 moles of CuCl_2 require = 2 moles of Al

Thus 0.33 moles of CuCl_2 will require=\frac{2}{3}\times 0.33=0.22moles  of Al

Thus CuCl_2 is the limiting reagent as it limits the formation of product and Al is the excess reagent.

As 3 moles of CuCl_2 give = 2 moles of AlCl_3

Thus 0.33 moles of CuCl_2 give =\frac{2}{3}\times 0.33=0.22moles  of AlCl_3

Theoretical yield of AlCl_3=moles\times {\text {Molar mass}}=0.22moles\times 133.34g/mol=29.3

Thus 29.3 g of aluminium chloride is formed.

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2 years ago
How are Celsius, Kelvin, and Fahrenheit scales similar? How are they different? Considering their differences, think of one scen
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3 years ago
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2 years ago
Some people must eat a low-sodium diet with no more than 2,000 mg of sodium per day. By eating 1 cracker, 1 pretzel, and 1 cooki
Leni [432]

Answer:

The amount of sodium is 32 mg per cracker, 49 mg per pretzel and 68 mg per cookie.

Explanation:

Let's assume amount of sodium is x mg per cracker, y mg per pretzel and z mg per cookie.

So, the following three equations can be written as per given information:

x+y+z = 149 ........(1)

8y+8z = 936 ........(2)

6x+7y = 535 .........(3)

From equation- (2), y+z = \frac{936}{8} = 117

By substituting the value of (y+z) in equation- (1) we get,

                          x = 149-(y+z) = 149-117 = 32

By substituting the value of x into equation- (3) we get,

                           y = \frac{535-(6\times 32)}{7} = 49

By substituting the value of y  into equation- (2) we get,

                           z = (117-49) = 68

So, the amount of sodium is 32 mg per cracker, 49 mg per pretzel and 68 mg per cookie.

6 0
3 years ago
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