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s344n2d4d5 [400]
3 years ago
14

You are given 230 grams of a substance with a half-life of 0.75 years. How much will remain after 3 years?

Chemistry
1 answer:
Degger [83]3 years ago
6 0
After 3 years, the substance will go through 4 half lives. You can do 230*(1/2)^4, which is 14.375.
You might be interested in
n the reaction Mg (s) + 2HCl (aq) H2 (g) + MgCl2 (aq), how many moles of hydrogen gas will be produced from 75.0 milliliters of
Xelga [282]
0.075 L * 1.0 M = 0.075 mol HCl
H2 is half of HCl by the coefficients divide 0.075 by 2 and get 0.0375 mol H2 gas
8 0
3 years ago
What is the ph of a 0.25 m solution of c6h5nh2 given that its kb is 1.8 x 10-6?
IrinaK [193]

The pH a 0.25 m solution of C₆H₅NH₂ is equal to 3.13.

<h3>How do we calculate pH of weak base?</h3>

pH of the weak base will be calculate by using the Henderson Hasselbalch equation as:

pH = pKb + log([HB⁺]/[B])

pKb = -log(1.8×10⁻⁶) = 5.7

Chemical reaction for C₆H₅NH₂ is:

                          C₆H₅NH₂ + H₂O → C₆H₅NH₃⁺ + OH⁻

Initial:                     0.25                           0            0

Change:                    -x                             x             x

Equilibrium:        0.25-x                           x             x

Base dissociation constant will be calculated as:
Kb = [C₆H₅NH₃⁺][OH⁻] / [C₆H₅NH₂]

Kb = x² / 0.25 - x

x is very small as compared to 0.25, so we neglect x from that term and by putting value of Kb, then the equation becomes:

1.8×10⁻⁶ = x² / 0.25

x² = (1.8×10⁻⁶)(0.25)

x = 0.67×10⁻³ M = [C₆H₅NH₃⁺]

On putting all these values on the above equation of pH, we get

pH = 5.7 + log(0.67×10⁻³/0.25)

pH = 3.13

Hence pH of the solution is 3.13.

To know more about Henderson Hasselbalch equation, visit the below link:
brainly.com/question/13651361

#SPJ4

5 0
2 years ago
Mitosis and Meiosis Lab Report
poizon [28]

Answer:

Mitosis and Meiosis Lab Report

Instructions: In the Mitosis and Meiosis lab, you investigated sexual and asexual reproduction as well as the processes of cellular division by mitosis and meiosis. Record your observations in the lab report below. You will submit your completed report.

________________________________________

Name and Title:  

Mitosis and Meiosis Lab Report.  

Objective(s):  

To learn and explore what mitosis and meiosis is and what they do.  

Hypothesis:

Record your predictions during the zoo tour section of the lab in the data chart.

Procedure:

First, go into the mitosis and meiosis cycles. Then look at what happens when a sex cell from a female tiger is combined with a sex cell from a male tiger. Then investigate what happens when two starfish reproduce asexually. Then write down the predictions about how each organism will replicate. Then, keep track on whether or not the forecast was right.

Data:  

Record your data from the zoo tour in the data chart below. Be sure to fill in the chart completely.

Zoo Organism Reproduction Prediction

(sexual, asexual, or both) Reproduction Result

(sexual, asexual, or both)

Elephant Sexual Sexual

Whiptail lizard Asexual Asexual

Parrot Sexual Sexual

Redwood tree  Both Both

Amoeba Asexual Asexual

Jellyfish Asexual Both

Conclusion:  

Your conclusion will include a summary of your lab results and an interpretation of the results. Please write in complete sentences.

1. List one-way mitosis and meiosis are the same and one way they are different.

Meiosis has 2 cell divisions, but mitosis has just one cell division. Since the parent cell develops diploid cells, meiosis I is the same as mitosis. The distinction between meiosis and mitosis is that after the whole process, meiosis produces genetically distinct haploid daughter cells, while mitosis produces genetically identical diploid daughter cells.

2. What is one advantage and one disadvantage of sexual reproduction?

The greatest benefit of sexual reproduction is that it aids in the development of offspring that are well suited to environmental environments due to genetic differentiation. As a result, the nation has a diverse range of descendants. The downside is that it needs two parents and takes longer than asexual reproduction.

3. What is one advantage and one disadvantage of asexual reproduction?

Asexual reproduction has the advantage of requiring only one parent, taking a short amount of time, and producing genetically identical offspring. The only drawback is that when there is a catastrophe, the mortality rate is poor due to the generation of genetically identical offspring.

4. Some living organisms are capable of both asexual and sexual reproduction. Explain how this can be an advantage.

To produce offspring, the organism may use either sexual or asexual reproduction. If it is difficult to find a mate, the living being will use asexual reproduction to produce offspring quickly. Sexual reproduction is possible because the individual requires genetically distinct offspring for survival.

Explanation:

Try to paraphrase evrything. I already paraphrased the procedure but i reccomend using the website "quillbot" to paraphrase evrything else so you dont get in trouble! If you have any qustions im here to answer ;)

6 0
2 years ago
Read 2 more answers
Compare the spectra produced by incandescent and fluorescent sources. Why is there a difference?
Inessa [10]
Both have a continuous light spectra the fluorescent source makes a spectra with more intense bands of mercury
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5 0
2 years ago
Read 2 more answers
A) Calculate the osmotic pressure difference between seawater and fresh water. For simplicity, assume thatall the dissolved salt
never [62]

Answer:

a)  Δπ = 1.264 atm

b) W = 128 joules

c)  ΔH >> W  ( a factor greater than 17,000 )

Explanation:

a) The osmotic pressure, π , is determined by :

π = nRT/V, where n= moles of solute

                          R= 0.0821 Latm/kmol

                          T = 300 K

calling π(sw) osmotic pressure for  for sea water and π (fw) for fresh water,

salinity of sea water = 3.5 g / 1L water   (assuming only NaCl for the salts)

salinity of fresh water = 0.5 parts per thousand (range: 0- 0.5 ppt)

πsw = (3.5 g/58.44 g/mol) (0.0821 Latm/Kmol) (300 K ) /1 L = 1.475 atm

πfw = (0.5 g/58.44 g/mol) (0.0821 Latm/Kmol) (300 K ) /1 L = 0.211 atm

d water = 1 g/cm³

Δ π = (1.475 - 0.211) = 1.264 atm

b) W = Δπ V = 1.426 atm x 1L = 1.43 L-atm

1 L-atm = 101.33 j

W =  101.33 j/ Latm x  1.43 Latm = 128 joules

c) ΔH = Q₁ + nΔH vap, where

            Q₁  = heat required to bring the solution from 300 K to boiling, 373 K

            ΔH vap = heat of vaporization

Q = mCΔT = 1000 g x 4.186 j x 73 K = 305.6 j = 0.3056 kj

ΔH vap = (1000 g/ 18 g/mol ) 40.7 kj/mol = 2,261 kj

ΔH =  0.3056 kj + 2,261 kj = 2,261.3 kj

Note = Q << ΔH vap and we could have neglected it.

This result shows why nobody talks about evaporation of sea water to produce fresh water ΔH >> W

6 0
3 years ago
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