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2 years ago

9

What is a molecule contains the genetic instructions for the development and functioning of all living organisms found in the nu

cleus of a cell

1 answer:

scoray [572]2 years ago

4 0

DNA (short for deoxyribonucleic acid)

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Name the following <br> Cr(SO4)2

inessss [21]

Chromium sulfate.
Cr is chromium, and SO4 is sulfate.

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3 years ago

H20+ SO3 ? Which compound is likely produced by the chemical reaction?

shusha [124]

Answer:

h2so4

Explanation:

im big brain.

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3 years ago

Read 2 more answers

Pls help me on this I have 5 minutes left to submit

pantera1 [17]

#1

Heterogenous mixture mean unsimilar substances .

Chicken noodle soyp.
salt water
propane.

#2

An element is a substance made of only one type of atoms

Example-Al,S

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2 years ago

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A 5.000 g mixture contains strontium nitrate and potassium bromide. Excess lead(II) nitrate solution is added to precipitate out

scZoUnD [109]

<u>Answer:</u> The mass percent of potassium bromide in the mixture is 9.996%

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

<u>For lead (II) bromide:</u>

Given mass of lead (II) bromide = 0.7822 g

Molar mass of lead (II) bromide = 367 g/mol

Putting values in equation 1, we get:

$\text{Moles of lead (II) bromide}=\frac{0.7822g}{367g/mol}=0.0021mol$

The chemical equation for the reaction of lead (II) nitrate and potassium bromide follows:

$2KBr+Pb(NO_3)_2\rightarrow PbBr_2+2KNO_3$

By Stoichiometry of the reaction:

1 mole of lead (II) bromide is produced from 2 moles of potassium bromide

So, 0.0021 moles of lead (II) bromide will be produced from = $\frac{2}{1}\times 0.0021=0.0042mol$ of potassium bromide

Now, calculating the mass of potassium bromide by using equation 1, we get:

Molar mass of KBr = 119 g/mol

Moles of KBr = 0.0042 moles

Putting values in equation 1, we get:

$0.0042mol=\frac{\text{Mass of KBr}}{119g/mol}\\\\\text{Mass of KBr}=0.4998g$

To calculate the percentage composition of KBr in the mixture, we use the equation:

$\%\text{ composition of KBr}=\frac{\text{Mass of KBr}}{\text{Mass of mixture}}\times 100$

Mass of mixture = 5.000 g

Mass of KBr = 0.4998 g

Putting values in above equation, we get:

$\%\text{ composition of KBr}=\frac{0.4998g}{5.000g}\times 100=9.996\%$

Hence, the percent by mass of KBr in the mixture is 9.996 %

5 0

3 years ago

Why are chemists interested in studying thermochemistry? a. Heat is often absorbed during reactions.b. Heat is often released du

Wittaler [7]

Answer:

a. Heat is often absorbed during reactions.

c. Heat is often released during chemical reactions.

Explanation:

Thermochemistry -

The study of thermochemistry involve the change in the amount of heat , during any physical or chemical process , is referred to as thermodynamics .

The focus of thermochemistry is on the changing amount of energy in the form of heat , on the system with respect to the surroundings .

The process like boiling , melting , sublimation , may require energy or releases energy , and hence are studied under thermochemistry .

Hence , from the given question ,

The correct options are - a , c.

6 0

3 years ago