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MariettaO [177]
3 years ago
11

PLS I NEED UR HELP QUICK ILL BRAINLIST Nd gIVE U 5 star. answer in full sentence!

Chemistry
1 answer:
Oxana [17]3 years ago
6 0

Explanation:

1) There are three sub atomic particles; protons, neutrons and electrons. Protons and Neutrons are found in the nucleus while electrons are found in orbitals outside the Nucleus.

2)  No. This is not always the case. An example is sodium which has atomic mass of 23.

Atomic Mass = Neutrons + Protons

23 = Neutrons + 11

Neutrons = 23 - 11 = 12

In sodium there are 11 protons and 12 neutrons

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The stationary state with the lowest energy is called the _______.
Olegator [25]

Answer:

Ground state

the state with the smallest amount of energy.

3 0
3 years ago
A 0.75M solution of CH3OH is prepared in 0.500 kg of water. How many moles of CH3OH are needed?
4vir4ik [10]

Answer:

We need 0.375 mol of CH3OH to prepare the solution

Explanation:

For the problem they give us the following data:

Solution concentration 0,75 M

Mass of Solvent is 0,5Kg

knowing that the density of water is 1g / mL,  we find the volume of water:

                           d = \frac{g}{mL} \\\\ V= \frac{g}{d}  = \frac{500g}{1 \frac{g}{mL} } = 500mL = 0,5 L

Now, find moles of CH_{3} OH are needed using the molarity equation:

                           M = \frac{ moles }{ V (L)} \\\\\\molesCH_{3}OH  = M . V(L) = 0,75 M . 0,5 L\\\\molesCH_{3}OH = 0,375 mol

therefore the solution is prepared using 0.5 L of H2O and 0.375 moles of CH3OH,  resulting in a concentration of 0,75M

5 0
3 years ago
The na+/k+ pump removes ______ na+ ions and adds _______ k+ ions.
Paladinen [302]

Sodium potassium pump is an active pump which transfer sodium and potassium ions across the membrane with the expenditure of energy in the form of ATP.

This kind of pump is generally used in nerve cells.

The pump works against the concentration gradient as the pump moves three Na+ ions outside the cell and two K+ ions inside the cell, though there is a high concentration of Na+ outside the cell and a low concentration of K+ outside the cell.

3 0
3 years ago
Match each term below with its definition or description.
zubka84 [21]

Answer:

1. Equivalence point

2. Direct titration

3. Primary standard

4. Titrand

5. Back titration

6. Standard solution

7. Titrant

8. Indirect titration

9. End point

10. Indicator

Explanation:

1. The equivalence point is the tiration point at which the quantity or moles  of the added titrant is sufficient or equal to the quantity or moles of the analyte for the neutralization of the solution of the analyte.

2. Direct titration is a method of quantitatively determining the contents of a substance

3. A primary standard is an easily weigh-able representative of the mount of moles contained in a substance

4. A titrand is the substance of unknown concentration which is to be determined

5. The titration method that uses a given amount of an excess reagent to determine the concentration of an analyte is known as back titration

6. A standard solution is a solution of accurately known concentration

7. A titrant is a solution that has a known concentration and which is titrated unto another solution to determine the concentration of the second solution

8. Indirect titration is the process of performing a titration in athe reverse order

9. The end point is the point at which the indicator indicates that the equivalent quantities of the reagents required for a complete reaction has been added

10 An indicator is a compound used to visually determine the pH of a solution.

5 0
3 years ago
If 100 ml of a 0.5 M HCI Solution is diluted with water to 1000ml, what is the new concetration?
Vesna [10]

Answer:

0.05\ \text{M HCl}

Explanation:

V_1 = Initial volume = 100 mL

V_2 = Final volume = 1000 mL

M_1 = Initial concentration = 0.5 M

M_2 = Final concentration

We have the relation

\dfrac{M_1}{M_2}=\dfrac{V_2}{V_1}\\\Rightarrow M_2=M_1\dfrac{V_1}{V_2}\\\Rightarrow M_2=0.5\times \dfrac{100}{1000}\\\Rightarrow M_2=0.05\ \text{M HCl}

The new concentration is 0.05\ \text{M HCl}.

3 0
3 years ago
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