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Alla [95]
3 years ago
15

Olivia looked under a microscope and saw tiny protists moving around on the slide from water in a pond near her house. She remem

bered what she
had learned about the cell theory as she observed the protists moving. Which three ideas are included in the cell theory?
A New cells are produced from existing cells
B. Cells are the basic units of structure and function of living organisms
C Cells are the basic units of structure and function in animals only
D. Cells divide when they begin to grow too large to function
E All living things are made of cells
E Cells are able to divide and produce new materials
their daughter cells.
Chemistry
1 answer:
DanielleElmas [232]3 years ago
3 0

Answer:

She remembered what she had learned about the cell theory as she observed the protists moving. Which three ideas are included in the cell theory ..

Explanation:

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457cg converted into dg
grigory [225]
1 cg ---------- 0.1 dg
457 cg ------- ?

457 x 0.1 / 1

= 45.7 dg
8 0
3 years ago
A 50.0-ml sample of 0.50 m hcl is titrated with 0.50 m naoh. what is the ph of the solution after 28.0 ml of naoh have been adde
hram777 [196]

The pH of the solution after addition of 28 mL of NaOH is added to HCl is \boxed{{\text{0}}{\text{.85}}} .

Further Explanation:

The proportion of substance in the mixture is called concentration. The most commonly used concentration terms are as follows:

1. Molarity (M)

2. Molality (m)

3. Mole fraction (X)

4. Parts per million (ppm)

5. Mass percent ((w/w) %)

6. Volume percent ((v/v) %)

Molarity is a concentration term that is defined as the number of moles of solute dissolved in one litre of the solution. It is denoted by M and its unit is mol/L.

The formula to calculate the molarity of the solution is as follows:

{\text{Molarity of solution}}=\dfrac{{{\text{Moles}}\;{\text{of}}\;{\text{solute}}}}{{{\text{Volume }}\left({\text{L}} \riht){\text{ of solution}}}}          

                             ......(1)        

                         

Rearrange equation (1) to calculate the moles of solute.

{\text{Moles}}\;{\text{of}}\;{\text{solute}}=\left( {{\text{Molarity of solution}}}\right)\left({{\text{Volume of solution}}}\right)       ......(2)

Substitute 0.50 M for the molarity of solution and 50 mL for the volume of solution in equation (2) to calculate the moles of HCl.

\begin{aligned}{\text{Moles}}\;{\text{of}}\;{\text{HCl}}&= \left({{\text{0}}{\text{.50 M}}}\right)\left( {{\text{50 mL}}} \right)\left( {\frac{{{\text{1}}{{\text{0}}^{ - 3}}{\text{ L}}}}{{{\text{1 mL}}}}} \right)\\&= 0.02{\text{5 mol}}\\\end{aligned}

Substitute 0.50 M for the molarity of solution and 28 mL for the volume of solution in equation (2) to calculate the moles of NaOH.

\begin{aligned}{\text{Moles}}\;{\text{of}}\;{\text{NaOH}}&=\left( {{\text{0}}{\text{.50 M}}} \right)\left( {{\text{28 mL}}} \right)\left( {\frac{{{\text{1}}{{\text{0}}^{ - 3}}{\text{ L}}}}{{{\text{1 mL}}}}}\right)\\&= 0.014{\text{ mol}}\\\end{aligned}

The reaction between HCl and NaOH occurs as follows:

{\text{NaOH}} + {\text{HCl}} \to {\text{NaCl}} + {{\text{H}}_2}{\text{O}}

The balanced chemical reaction indicates that one mole of NaOH reacts with one mole of HCl. So the amount of remaining HCl can be calculated as follows:

\begin{aligned}{\text{Amount of HCl remaining}}&= 0.02{\text{5 mol}} - 0.01{\text{4 mol}}\\&= {\text{0}}{\text{.011 mol}} \\\end{aligned}

The volume after the addition of NaOH can be calculated as follows:

\begin{aligned}{\text{Volume of solution}} &= {\text{50 mL}} + {\text{28 mL}}\\&= {\text{78 mL}}\\\end{aligned}

Substitute 0.011 mol for the amount of solute and 78 mL for the volume of solution in equation (1) to calculate the molarity of new HCl solution.

\begin{aligned}{\text{Molarity of new HCl solution}}&= \left({{\text{0}}{\text{.011 mol}}} \right)\left( {\frac{1}{{{\text{78 mL}}}}}\right)\left( {\frac{{{\text{1 mL}}}}{{{{10}^{ - 3}}\;{\text{L}}}}} \right)\\&= 0.1410{\text{2 M}}\\&\approx {\text{0}}{\text{.141 M}}\\\end{aligned}

pH:

The acidic strength of an acid can be determined by pH value. The negative logarithm of hydronium ion concentration is defined as pH of the solution. Lower the pH value of an acid, the stronger will be the acid. Acidic solutions are likely to have pH less than 7. Basic or alkaline solutions have pH more than 7. Neutral solutions have pH equal to 7.

The formula to calculate pH of an acid is as follows:

{\text{pH}}=- {\text{log}}\left[ {{{\text{H}}^ + }}\right]     ......(3)

Here,

\left[{{{\text{H}}^ + }}\right] is hydrogen ion concentration.

HCl is a strong acid so it dissociates completely. So the concentration of   also becomes 0.141 M.

Substitute 0.141 M for \left[{{{\text{H}}^ + }}\right] in equation (3).

\begin{aligned}{\text{pH}}&= - {\text{log}}\left({0.141} \right)\\&=0.85\\\end{aligned}

So the pH of the solution is 0.85.

Learn more:

1. Which indicator is best for titration between HI and  ? brainly.com/question/9236274

2. Why is bromophenol blue used as an indicator for antacid titration? brainly.com/question/9187859

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Acid-base titrations

Keywords: molarity, pH, HCl, NaOH, 0.85, 0.141 M, moles of HCl, moles of NaOH, 50 mL, 0.50 M, 28 mL, 0.025 mol, 0.014 mol, 0.011 mol, 78 mL.

4 0
3 years ago
Read 2 more answers
If one mole of PtCl2·3NH3 reacts with AgNO3 to produce one mole of AgCl(s), how can the formula PtCl2·3NH3 be re-written to show
kap26 [50]
Don't bet any money on this but I think its [Pt(NH3)3] Cl2
6 0
3 years ago
Help on science please!! Will bark brainliest!
jok3333 [9.3K]

Aphelion in miles =94290301

Perihelion in miles = 91200281

Explanation:

To convert km in mile we use the multiply the distance in km with 0.62, because there are 0.62 miles in 1 km.

Aphelion in miles = aphelion in km × 0.62

Aphelion in miles = 152081132 × 0.62

Aphelion in miles =94290301

Perihelion in miles = perihelion in km × 0.62

Perihelion in miles = 147097229 × 0.62

Perihelion in miles = 91200281

Learn more about:

conversion of units

brainly.com/question/5725710

brainly.com/question/5956394

#learnwithBrainly

7 0
3 years ago
Hurry. NO Spam! Write the neutralization reaction that occurs between HF and LiOH.
tekilochka [14]

Answer:

HF + LiOH = LiF + H2O.

Explanation:

Hydofluoric acid is a weak acid the solution would be slightly basic due to the following equilibrium (condition in the course of a reversible chemical reaction in which no net change in the amounts of reactants and products occurs.)

Hope that helps. x

4 0
3 years ago
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