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3 years ago

a sample that has a half life of 45 years take ____ for the count rate to drop from 600 cpm to 150 cpm

Chemistry

1 answer:

Bond [772]3 years ago

5 0

Answer:

90yrs

Explanation:

Half life is the time taken for half of an original radioactive material to decay by half.

For the sample;

Half - life = 45yrs

Original amount = 600cpm

Start Number of atoms

0yrs 600cpm

First half life

45yrs 300cpm

Second half life

90yrs 150cpm

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pav-90 [236]

<h3>Answer:</h3>

388.94 g N₂

<h3>General Formulas and Concepts:</h3>

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Chemistry

Atomic Structure

Reading a Periodic Table
Using Stoichiometry

<h3>Explanation:</h3>

Step 1: Define

[RxN] 4HCl (g) + 6NO (g) → 5N₂ (g) + 6H₂O (g)

[Given] 404.87 g HCl

Step 2: Identify Conversions

[RxN] 4 mol HCl = 5 mol N₂

Molar Mass of H - 1.01 g/mol

Molar Mass of Cl - 35.45 g/mol

Molar Mass of HCl - 1.01 + 35.45 = 36.46 g/mol

Molar Mass of N - 14.01 g/mol

Molar Mass of N₂ - 2(14.01) = 28.02 g/mol

Step 3: Stoichiometry

$404.87 \ g \ HCl(\frac{1 \ mol \ HCl}{36.46 \ g \ HCl} )(\frac{5 \ mol \ N_2}{4 \ mol \ HCl} )(\frac{28.02 \ g \ N_2}{1 \ mol \ N_2} )$ = 388.935 g N₂

Step 4: Check

We are given 5 sig figs. Follow sig fig rules and round.

388.935 g N₂ ≈ 388.94 g N₂

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