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3 years ago

How many atoms are in a sample of 72.8 grams calcium ?

1 answer:

6 0

First find the moles
moles of the calcium= 72.8 / 40
moles of calcium in 72.8g = 1.82mol

number of atoms= moles x Avogadro constant
atoms = 1.82 x 6.02x10+23
so the number of atoms is 1.096x10+24

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Which atom would form a cation? F Na N P

sineoko [7]

Answer:

I believe Na

Explanation:

Copper, because it is the only metal out of all of them.

Therefore copper is the only element that can loose electrons to have a positive charge, it is the most likely to become a cation.

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3 years ago

What is the purpose of adding phenolphthalein to your Erlenmeyer flask prior to starting a titration?

koban [17]

Answer:

a. The phenolphthalein acts as a color changing indicator to signal the endpoint of the reaction.

Explanation:

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It is a substance commonly used in acid-base titrations to indicate the end point in the titration because phenolphthalein is colorless in acidic solutions but turns a purplish-pink color in basic solutions.

In this way it helps visually to notice when the final point of the titration has been reached.

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3 years ago

What is the name of cells that have the ability to develop into different kinds of cells?

ser-zykov [4K]

Answer:

stem cells

Explanation:

hope it helps

8 0

3 years ago

You made hypochlorous acid (HOCI) by mixing bleach (NaOCI) with:

Annette [7]

Answer: When bleach is mixed with water, it produces hypochlorous acid.

Explanation:

The chemical name for bleach is sodium hypochlorite. When this compound is reacted with water, it produces hypochlorous acid and sodium hydroxide.

The chemical equation for the reaction of sodium hypochlorite and water follows:

$NaOCl+H_2O\rightarrow HOCl+NaOH$

By Stoichiometry of the reaction:

1 mole of sodium hypochlorite reacts with 1 mole of water to produce 1 mole of hypochlorous acid and 1 mole of sodium hydroxide.

Hence, when bleach is mixed with water, it produces hypochlorous acid.

6 0

3 years ago

A compound with a molar mass of 100.0 g/lol has an elemental composition of 24.0% C, 3.0% H, 16.0% O and 57.0%F. What is the mol

ch4aika [34]

If I made no mistake in calculation, the given answer must be correct...(tried my best)

elements   :                       carbon     hydrogen    oxygen       Fluorine

composition [C]                     24           3                16                57

M r                                          12             1                16                19

(divide C by Mr)                       2               3                 1                  3

(Divide by smallest value)       2                3                  1                  3

(smallest value = 1...so all value remained constant)

Empirical formula : C2H3OF3

if molar mas = 100 g per mole, then

first step calculate Mr. of empirical formula: [= 100]

Them molecular formula = empirical formula

7 0

3 years ago