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2 years ago

Please help me with these questions I don't get science

Chemistry

2 answers:

ipn [44]2 years ago

6 0

There are at least 60 elements in our bodies.

Other elements may be present, but in such small quantities that we cannot detect them with current technologies.

The six most abundant elements (by mass) in our bodies are:

Oxygen 65 %

Carbon 18 %

Hydrogen 10 %

Nitrogen 3.2 %

Calcium 1.4 %

Phosphorus 1.1 %

TOTAL = 99 %

LiRa [457]2 years ago

4 0

Proteins are made of carbon, hydrogen,oxygen, and nitrogen (CHON). Nucleic acids such as DNA and RNA contain carbon,hydrogen, oxygen, nitrogen, and phosphorus(CHON P). The body also needs trace amounts of other elements such as calcium,potassium, and sulfur for proper functioning of muscles, nerves, etc.

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When metals, non metals,and metallics are composed according to luster, which is best description of the appearance of metalloid

Nitella [24]

Answer:

Metalloids are metallic-looking brittle solids that are either semiconductors or exist in semiconducting forms, and have amphoteric or weakly acidic oxides. Typical nonmetals have a dull, coloured or colourless appearance; are brittle when solid; are poor conductors of heat and electricity; and have acidic oxides.

Explanation:

5 0

2 years ago

At 25 °C, how many dissociated OH– ions are there in 1243 mL of an aqueous solution whose pH is 2.07?

coldgirl [10]

Answer: The number of $OH^-$ ions dissociated are $8.57\times 10^{11}$

Explanation:

We are given:

pH = 2.07

Calculating the value of pOH by using equation, we get:

$2.07+pOH=14\\\\pOH=14-2.07=11.93$

To calculate hydroxide ion concentration, we use the equation to calculate pOH of the solution, which is:

$pOH=-\log[OH^-]$

We are given:

pOH = 11.93

Putting values in above equation, we get:

$11.93=-\log[OH^-]$

$[OH^-]=10^{-11.93}=1.17\times 10^{-12}M$

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of solution = $1.17\times 10^{-12}M$

Volume of solution = 1243 mL = 1.243 L (Conversion factor: 1 L = 1000 mL)

Putting values in above equation, we get:

$1.17\times 10^{-12}M=\frac{\text{Moles of }OH^-}{1.243L}\\\\\text{Moles of }OH^-=(1.17\times 10^{-12}mol/L\times 1.243L)=1.424\times 10^{-12}mol$

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of particles

So, $1.424\times 10^{-12}mol$ number of $OH^-$ will contain = $(1.424\times 10^{-12}\times 6.022\times 10^{23})=8.57\times 10^{11}$ number of ions

Hence, the number of $OH^-$ ions dissociated are $8.57\times 10^{11}$

3 0

3 years ago

Concentrated 8.2 of commercial chloride or chlorox diluted to 14% ?

ELEN [110]

Is it 8.06?

Or 58.57?

Don't get mad if there wrong!!
But please let me know if it's right or wrong tho.

7 0

3 years ago

Mechanically weathered rock is broken down into smaller _________________________. (four word phrase)

scoundrel [369]

Weathering because Weathering is the process where rock is dissolved, worn away or broken down into smaller and smaller pieces. There are mechanical, chemical and organic weatheringprocesses. Organic weathering happens when plants break up rocks with their growing roots or plant acids help dissolve rock.

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2 years ago

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What is the most important change in a chemical change?

avanturin [10]

5) state
when the state of the chemical changes that is the most important

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2 years ago