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3 years ago

5. Rosalind Franklin was a key figure in the discovery of the structure of DNA, yet she

Chemistry

1 answer:

andreev551 [17]3 years ago

3 0

Answer:

Explanation:

Search for "Rosalind Franklin: DNA's unsung hero - Cláudio L. Guerra" which basically summarizes what Rosalind did and how we was snubbed from receiving the noble prize even though she had vast and critical evidence to highlight the structure of DNA. You can look for more sources but I can tell you a quick recap:

Rosalind Franklin was born in an era where women scientists or workers were very uncommon and they were even discriminated and looked down upon. After her phD., she was working to find the structure of DNA and soon she was able to form an x-ray image of it. However, her lab colleague took the picture and showed it to other scientists (Watson and Crick) without the knowledge or permission of Rosalind. Here Rosalind was working on analyzing her data and on other part of world Watson and Crick were doing the same. Based on Watson and Crick's analysis, they came up with the correct structure of DNA and soon Rosalind got done as well. Both submitted their paper to journal, however, the journal placed Watson and Crick paper before Rosalind (making it look like Rosalind just confirmed what Watson and Crick proposed). This made it look like Watson and Crick were geniuses behind DNA structure whereas, in reality, it was Rosalind. She would have received Nobel Prize but she died of Cancer and Nobel prizes are not awarded to dead people.

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Consider an electron placed in a region of space in which the electric potential spatially. The electron is placed at a point wh

loris [4]

Answer:

$1.33\cdot 10^7 m/s$

Explanation:

For a charged particle accelerated by an electric field, the kinetic energy gained by the particle is equal to the decrease in electric potential energy of the particle; therefore:

$K_f-K_i = -q\Delta V$

where

$K_f$ is the final kinetic energy

$K_i$ is the initial kinetic energy

q is the charge of the particle

$\Delta V$ is the potential difference

In this problem,

$q=-1.6\cdot 10^{-19}C$ is the charge of the electron

$\Delta V=-500 V-(-1000 V)=500 V$

The electron starts from rest, so its initial kinetic energy is

$K_i=0$

Therefore,

$K_f=-(-1.6\cdot 10^{-19})(500)=8\cdot 10^{-17}J$

We can write the final kinetic energy of the electron as

$K_f=\frac{1}{2}mv^2$

where

$m=9.11\cdot 10^{-31} kg$ is the electron mass

v is the final speed

And solving for v,

$v=\sqrt{\frac{2K_f}{m}}=\sqrt{\frac{2(8\cdot 10^{-17})}{9.11\cdot 10^{-31}}}=1.33\cdot 10^7 m/s$

5 0

3 years ago

How many grams are in 2.3 x 10^-4 moles of Ca3(PO4)2

OLEGan [10]

Molar mass

Ca₃(PO₄)₂ = 310 g/mol

1 mole -------------------> 310 g
2.3x10⁻⁴ mole ---------> ?

m = 2.3x10⁻⁴ * 310 / 1

m = 0.0713 g

hope this helps!

3 0

3 years ago

A 1.555-g sample of baking soda decomposes with heat to produce 0.991 g Na2CO3. Refer to Example Exercise 14.l and show the calc

Sunny_sXe [5.5K]

Answer:

a) 101%

b)59.7%

Explanation:

The equation for the thermal decomposition of baking soda is shown;

2NaHCO3 → Na2CO3 + H2O + CO2

Number of moles of baking soda= mass/molar mass= 1.555g/84.007 g/mol = 0.0185 moles

From the reaction equation;

2 moles of baking soda yields 1 mole of sodium carbonate

0.0185 moles of baking soda will yield = 0.0185 moles ×1 /2 = 9.25 ×10^-3 moles of sodium carbonate.

Therefore, mass of sodium carbonate= 9.25 ×10^-3 moles × 106gmol-1= 0.9805 g of sodium carbonate. This is the theoretical yield of sodium carbonate.

%yield = actual yield/theoretical yield ×100

% yield = 0.991/0.9805 ×100

%yield = 101%

Since ;

2NaHCO3 → Na2CO3 + H2O + CO2

And H2O + CO2 ---> H2CO3

Hence I can write, 2NaHCO3 → Na2CO3 + H2CO3

Molar mass of H2CO3= 62.03 gmol-1

Molar mass of baking soda= 84 gmol-1

Therefore, mass of baking soda=

0.325/62.03 × 2 × 84 = 0.88 g of NaHCO3

% of NaHCO3= 0.88/1.473 × 100 = 59.7%

7 0

2 years ago

A certain compound is made up of one phosphorus (P) atom, three chlorine (Cl) atoms, and one oxygen (O) atom. What is the chemic

yulyashka [42]

Answer: PCl₃O

Explanation:

1) The chemical formula tells the composition of a compound in terms of the ratio of number of atoms of each element that consitutes such compound.

2) You use the chemical symbol for each kind of atom (element) and subscripts to the right of each symbol to tell the number of atoms of each element.

3) For example, O₂ means two atoms of oxygen. Al₂O₃ means two atoms of aluminum and 3 atoms of oxygen.

4) Therefore, PCl₃O means a ratio 1 : 3 : 1 for phosphorus, chlorine, and oxygen.

Hence, PCl₃O is the chemical formula of your compound.

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3 years ago

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Is water in a kettle boiling a chemical change

Luden [163]

When a kettle is boiling you are able to see the chemical reaction, from the stem leaving the kettle, so yes
Hope this helped : )

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2 years ago

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