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zubka84 [21]
2 years ago
11

There are 5.0g of I-131 left after 40 days. How many grams were in the original sample if the half-life is 8 days?

Chemistry
1 answer:
Gre4nikov [31]2 years ago
5 0
5.0=mo(1/2) ^ 5
5.0=mo (.031)
about 160/161.29
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Rank the following solutions in order of increasing acidity (least acidic to most acidic): I: [H3O+] = 1x10−5 II: [OH−] = 1x10−1
kozerog [31]

Answer: option C) II < III < I

i.e [OH−] < [H3O+] < I

Explanation:

First, obtain the pH value of I and II, then compare both with III.

For I

Recall that pH = -log (H+)

So pH3O = -log (H3O+)

= - log (1x10−5)

= 4

For II

pOH = - log(OH-)

= - log(1x10−10)

= 9

For III

pH = 6

Since, pH range from 1 to 14, with values below 7 to be acidic, 7 to be neutral, above 7 to be alkaline: then, 9 < 6 < 4

Thus, the following solutions from least acidic to most acidic is II < III < I

6 0
3 years ago
What are 4 general properties of matter?
Law Incorporation [45]
1. Solid
2. Liquid
3. Gas
4. Plasma
3 0
2 years ago
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What does a straight line represent on a distance vs time graph?
stellarik [79]
A straight line on a distance va time graph represents constant speed
3 0
3 years ago
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Minerals are very useful to us. Which of the following is a false statement? Question options: Pyrite is an ore of gold and is u
lilavasa [31]

Answer:

The false statement is :

  • Pyrite is an ore of gold and is used in jewelry making.
  • Cobalt is not used in medicine.

Explanation:

Pyrite is an ore of iron sulfide found on the Earth and in coal, limestone and in many deposits of metallic ores. Due to its luster and pale yellowish color it appears as gold due to which it is also termed as Fool's gold.

It is used in firearms , in production of sulfur dioxide gas, etc.

Cobalt is used as medicine to treat cancer patient. Co-60 is used in treatment of cancer in which gamma rays produced by Co-60 are used  to kill tumor cells in a cancer patient.

Where as talc is used in industries like : paper making, food, paints, plastics etc. Quartz is primary material used to prepare glass and cobalt is used as

4 0
3 years ago
How many formula units are there in 50.3 moles potassium chloride?
Alona [7]
<h3>Answer:</h3>

3.03 × 10²⁵ formula units KCl

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

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

  1. Brackets
  2. Parenthesis
  3. Exponents
  4. Multiplication
  5. Division
  6. Addition
  7. Subtraction
  • Left to Right

<u>Chemistry</u>

<u>Unit 0</u>

  • Reading a Periodic Table
  • Writing Compounds

<u>Atomic Structure</u>

  • Using Dimensional Analysis
  • Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<h3>Explanation:</h3>

<u>Step 1: Define</u>

50.3 mol KCl (Potassium chloride)

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

<u />\displaystyle 50.3 \ mol \ KCl(\frac{6.022 \cdot 10^{23} \ formula \ units \ KCl}{1 \ mol \ KCl} ) = 3.02907 × 10²⁵ formula units KCl

<u>Step 4: Check</u>

<em>We are given 3 sig figs. Follow sig fig rules and round.</em>

3.02907 × 10²⁵ formula units KCl ≈ 3.03 × 10²⁵ formula units KCl

6 0
3 years ago
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