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Ivan
2 years ago
5

How long will it take for a 40.0 gram sample of I-131 (half-life = 8.4 days) to decay to 1/16 its original mass?

Chemistry
1 answer:
Shtirlitz [24]2 years ago
6 0

Answer:

42 days

Explanation:

Half life = 8.4 days

Starting mass = 40.0 g

Time = ?

Final Mass = 1/16 * 40 = 2.5 g

First Half life;

Remaining mass = 40 / 2 = 20g

Second Half life;

Remaining mass = 20 / 2 = 10g

Third Half life;

Remaining mass = 10 / 2 = 5g

Fourth Half life;

Remaining mass = 5 / 2 = 2.5g

Time = Number of half lives * Duration of half life = 5 * 8.4 = 42 days

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What is the covalent bond for Hydrogen + Chlorine (HCI)
kolbaska11 [484]

Answer:

HCl, also known as hydrochloric acid, has a covalent bond. The hydrogen (H) atom shares an electron with the chlorine (Cl) to form the bond.

Explanation:

Consequently, the bonding electrons in hydrogen chloride are shared unequally in a polar covalent bond. The molecule is represented by the conventional Lewis structure, even though the shared electron pair is associated to a larger extent with chlorine than with hydrogen.

6 0
2 years ago
How many grams of Cl are in 525g of CaCl2
Tema [17]

First we determine the moles CaCl2 present:

525g / (110.9g/mole) = 4.73 moles CaCl2 present 

Based on stoichiometry, there are 2 moles of Cl for every mole of CaCl2:<span>
(2moles Cl / 1mole CaCl2) x 4.73 moles CaCl2 = 9.47 moles Cl </span>

Get the mass:<span>
<span>9.47moles Cl x 35.45g/mole = 335.64 g Cl</span></span>

8 0
3 years ago
Which of the following is the quantum number set for an electron in the 3rd energy level, dumb-bell shaped orbital, on the z-axi
Juli2301 [7.4K]

Answer:

Explanation:

Principal quantum no "n" = 3

Azimuthal quantum no "l"= 1

Magnetic quantum no "m"= +1/2

Over all is 3pz

5 0
2 years ago
how much heat will be absorbed by 25g of chloroform when its temperature started at 67.0C and after it was 112.0C
snow_tiger [21]

Hello friend ☺

ΔH = MCΔT

ΔH = to the amount of energy or change in energy (J)

mass of water

C = waters specific heat capacity

ΔT = change in temperature

and so ΔH = 25 × 4.18 × ( 112-67 ) J = 4702.5 J

Thanks ❤

8 0
3 years ago
Omg pls help i dunno what the frick frack this is
snow_lady [41]

Answer:

1. Mass of KCl produced = 774.8 g of KCl

2. Mass of KNO₃ produced = 13.837g

3. Moles of NaOH made = 0.846 moles

4. Moles of LiCl produced = 0.846 moles

5. Moles of CO₂ produced = 207.6 moles

Explanation:

1. From the equation of reaction, 1 mole of ZnCl₂ produces, 2 moles of KCl.

5.02 moles of ZnCl₂ will produce, 2 × 5.02 moles of KCl = 10.4 moles of KCl

Molar mass of KCl = (39 + 35.5) g/mol = 74.5 g/mol

10.4 moles of KCl = 10.4 × 74.5 g

Mass of KCl produced = 774.8 g of KCl

2. Mole ratio of KNO₃ and KOH = 1:1

O.137 moles of KOH will produce 0.137 moles of KNO₃

Molar mass of KNO₃ = 101 g/mol

Mass of KNO₃ produced = 0.137 × 101 g = 13.837g

3. Molar mas of Ca(OH)₂ = 74.0 g

Moles of Ca(OH)₂ in 31.3 g = 31.3/74.0 = 0.423 moles of Ca(OH)₂

Mole ratio of NaOH and Ca(OH)₂ in the reaction = 2 : 1

Moles of NaOH made = 2 × 0.423 = 0.846 moles

4. Molar mass of MgCl₂ = 95.0 g

Moles of MgCl₂ in 40.2 g = 40.2/95.0 = 0.423 moles

From the reaction equation, mole ratio of MgCl₂ and LiCl = 1:2

Moles of LiCl produced = 2 × 0.423 = 0.846 moles

5. From the equation of reaction, 1 mole of C₆H₁₀O₅ produces 6 moles of cO₂

34.6 moles of C₆H₁₀O₅ will produce 34.6 × 6 moles of CO₂

Moles of CO₂ produced = 207.6 moles

4 0
2 years ago
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