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never [62]
2 years ago
8

How long will it take a piece of strontium-90 (produced in a nuclear test blast) weighing exactly 1000.0 g to be

Chemistry
1 answer:
Nonamiya [84]2 years ago
7 0

Answer:

Time taken 172.8 years

Explanation:

Given data:

Total amount of strontium-90 = 1000.0 g

Amount left = 15.625 g

Half life of strontium = 28.8 years

Time taken = ?

Solution:

Number of half lives:

At time zero = 1000.0 g

At first half life = 1000.0g/2 = 500 g

At second half life = 500 g/2 = 250 g

At third half life = 250 g/ 2 = 125 g

At 4th half life = 125 g/ 2= 62.5 g

At 5th half life = 62.5 g/2 = 31.25 g

At 6th half life = 31.25 g / 2 = 15.625 g

Time taken:

Time taken = number of half lives × half life

Time taken = 6×28.8 years

Time taken = 172.8 years

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Scilla [17]

Answer: 1.  C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur

2. B)  NH_3

3. B) Fluorine

Explanation:

1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.

Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7

Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.

2. A molecular compound is usually composed of two or more nonmetal elements. Example: NH_3

Ionic compound is formed by the transfer of electrons from metals to non metals. Example: Mg_3N_2 , AlCl_3 and LiBr

3.  For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas F_2

4 0
2 years ago
Explain the flexibility and the flow characteristics of water​
Morgarella [4.7K]

Explanation:

Flow-duration data are daily mean flow values measured over a specified time interval that have been exceeded various percentages of the specified time interval.

5 0
3 years ago
Identify each element below, and give the symbols of the other elements in its group:
lozanna [386]

Answer:

Answer in explanation

Explanation:

Argon has 18 electrons. So to get the element in question, we only need to add 18 to the number of the filled electrons.

a. Germanium, atomic number 32

Other group members:

Silicon Si , Carbon C , Tin Sn , Lead Pb and Flerovium Fl

b. Cobalt , atomic number 27

Other group members:

Rhodium Rh , Iridium Ir and Meitnerium Mt

c. Technetium , atomic number 43

Krypton is element 36

Other group members are :

Manganese Mn , Rhenium Re and Bohrium Bh

7 0
3 years ago
which structures are found in eukaryotic cells a.chloroplast b. membrane bound organelles c. mitochondria d. nucleus e. pili
olasank [31]
Is it asking for multiple answers? 
If not the nucleus is one organelle found in the <span>eukaryotic.
Hope This Helps :)</span>
4 0
2 years ago
Read 2 more answers
7.5 moles of nitrogen gas (N2) is formed in the following reaction. How many grams
AfilCa [17]

Answer:

Mass = 255 g

Explanation:

Given data:

Number of moles of nitrogen = 7.5 mol

Mass of ammonia formed = ?

Solution:

Chemical equation:

3H₂ + N₂      →    2NH₃

Now we will compare the moles of nitrogen and ammonia.

             N₂         :        NH₃

               1          :         2

              7.5       :       2/1×7.5 = 15

Mass of ammonia:

Mass = number of moles × molar mass

Mass = 15 mol × 17 g/mol

Mass = 255 g

6 0
2 years ago
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