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3 years ago

PLZ HELLLLPPPP

Chemistry

1 answer:

coldgirl [10]3 years ago

6 0

D. The nucleus is the control center of the cell

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How many of the planets have an orbital period of less than one Earth year?

GrogVix [38]

Since orbital period depends on how far you are from the sun, planets closer to the sun have a orbital period less than one earth year.

These planets are Mercury and Venus

8 0

3 years ago

For all of the following questions 20.00 mL of 0.200 M HBr is titrated with 0.200 M KOH.

HACTEHA [7]

Answer :

The concentration of $H^+$ before any titrant added to our starting material is 0.200 M.

The pH based on this $H^+$ ion concentration is 0.698

Explanation :

First we have to calculate the concentration of $H^+$ before any titrant is added to our starting material.

As we are given:

Concentration of HBr = 0.200 M

As we know that the HBr is a strong acid that dissociates complete to give hydrogen ion $H^+$ and bromide ion $Br^-$ .

As, 1 M of HBr dissociates to give 1 M of $H^+$

So, 0.200 M of HBr dissociates to give 0.200 M of $H^+$

Thus, the concentration of $H^+$ before any titrant added to our starting material is 0.200 M.

Now we have to calculate the pH based on this $H^+$ ion concentration.

pH : It is defined as the negative logarithm of hydrogen ion concentration.

$pH=-\log [H^+]$

$pH=-\log (0.200)$

$pH=0.698$

Thus, the pH based on this $H^+$ ion concentration is 0.698

3 0

3 years ago

Rocks are solids composed of one or more minerals true or false

Yuki888 [10]

The answer is true
:)

8 0

3 years ago

4. The type of thermal energy transfer that heats our homes is called

andrew-mc [135]

Answer:

conduction is the answer

6 0

3 years ago

You have 363 mL of a 1.25M potassium chloride solution, but you need to make a 0.50M potassium chloride solution. How many milli

maxonik [38]

Answer:- 544.5 mL of water need to be added.

Solution:- It is a dilution problem. The equation used for solving this type of problems is:

$M_1V_1=M_2V_2$

where, $M_1$ is initial molarity and $M_2$ is the molarity after dilution. Similarly, $V_1$ is the volume before dilution and $V_2$ is the volume after dilution.

Let's plug in the values in the equation:

$1.25M(363mL)=0.50M(V_2)$

$V_2=\frac{1.25M(363mL)}{0.50M}$

$V_2=907.5mL$

Volume of water added = 907.5mL - 363mL = 544.5 mL

So, 544.5 mL of water are need to be added to the original solution for dilution.

3 0

3 years ago