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7nadin3 [17]
3 years ago
6

Answer my my science homework please

Chemistry
1 answer:
ludmilkaskok [199]3 years ago
5 0
1. D

2. <span>83.5 million years ago - 66 million years ago

3. </span><span>It had armor and could rotate to keep its caudal bludgeon facing the enemy.

hope this helped :)
alisa202</span>
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At 25∘C, the decomposition of dinitrogen pentoxide, N2O5(g), into NO2(g) and O2(g) follows first-order kinetics with k=3.4×10−5
Annette [7]

Answer:

4600s

Explanation:

2N_{2}O_{5}(g) - - -> 4NO_{2}(g) +O_{2}

For a first order reaction the rate of reaction just depends on the concentration of one specie [B] and it’s expressed as:

-\frac{d[B]}{dt}=k[B] - - -  -\frac{d[B]}{[B]}=k*dt

If we have an ideal gas in an isothermal (T=constant) and isocoric (v=constant) process.

PV=nRT we can say that P = n so we can express the reaction order as a function of the Partial pressure of one component.  

-\frac{d[P(B)]}{P(B)}=k*dt  

-\frac{d[P(N_{2}O_{5})]}{P(N_{2}O_{5})}=k*dt

Integrating we get:

\int\limits^p \,-\frac{d[P(N_{2}O_{5})]}{P(N_{2}O_{5})}=\int\limits^ t k*dt

-(ln[P(N_{2}O_{5})]-ln[P(N_{2}O_{5})_{o})])=k(t_{2}-t_{1})

Clearing for t2:

\frac{-(ln[P(N_{2}O_{5})]-ln[P(N_{2}O_{5})_{o})])}{k}+t_{1}=t_{2}

ln[P(N_{2}O_{5})]=ln(650)=6.4769

ln[P(N_{2}O_{5})_{o}]=ln(760)=6.6333

t_{2}=\frac{-(6.4769-6.6333)}{3.4*10^{-5}}+0= 4598.414s

4 0
3 years ago
Which type of formula represents the simplest whole-number ratio of atoms of the elements in a compound?
sleet_krkn [62]
The empirical formula represents the simplest whole number shows the simplest whole number ratio of atoms in a compound.  An example of this is the empirical formula for glucose (C₆H₁₂O₆) is C₃H₆O₃.  

I hope this helps.  Let me know if anything is unclear.
5 0
3 years ago
65 POINTS AND BRAINLIEST PLEASE HELP ASAP
Naily [24]

Answer:

Rosalind Elsie Franklin (25 July 1920 – 16 April 1958)was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal and graphite. The DNA work achieved the most fame because DNA (deoxyribonucleic acid) plays essential roles in cell metabolism and genetics, and the discovery of its structure helped scientists understand how genetic information is passed from parents to children.

rosalindfranklin

Franklin is best known for her work on the X-ray diffraction images of DNA which led to discovery of DNA double helix. Her data, according to Francis Crick, was "the data we actually used" to formulate Crick and Watson's 1953 hypothesis regarding the structure of DNA.Franklin's X-ray diffraction image confirming the helical structure of DNA were shown to Watson without her approval or knowledge. Though this image and her accurate interpretation of the data provided valuable insight into the DNA structure, Franklin's scientific contributions to the discovery of the double helix are often overlooked. Unpublished drafts of her papers (written just as she was arranging to leave King's College London) show that she had independently determined the overall B-form of the DNA helix and the location of the phosphate groups on the outside of the structure. However, her work was published third, in the series of three DNA Nature articles, led by the paper of Watson and Crick which only hinted at her contribution to their hypothesis.

After finishing her portion of the DNA work, Franklin led pioneering work on the tobacco mosaic and polio viruses. She died in 1958 at the age of 37 from complications arising from ovarian cancer.

3 0
3 years ago
What is the mass of sodium (Na) in 50 grams of table salt (NaCl)? Show your work.
Margaret [11]

Answer:

19 g

Explanation:

Data Given:

Sodium Chloride (table salt) = 50 g

Amount of sodium (Na) = ?

Solution:

Molecular weight calculation:

NaCl = 23 + 35.5

NaCl = 58.5 g/mol

Mass contributed by Sodium = 23 g

calculate the mole percent composition of sodium (Na) in sodium Chloride.

Since the percentage of compound is 100

So,

Percent of sodium (Na) = 23 / 58.5 x 100

Percent of sodium (Na) = 39.3 %

It means that for ever gram of sodium chloride there is 0.393 g of Na is present.

So,

for the 50 grams of table salt (NaCl) the mass of Na will be

mass of sodium (Na) = 0.393 x 50 g

mass of sodium (Na) = 19 g

8 0
4 years ago
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4 total bonds if u have double,or triple then subtract from 4
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4 years ago
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