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Sedaia [141]
3 years ago
11

Can someone help me, please?

Chemistry
1 answer:
VikaD [51]3 years ago
7 0
15. D is correct, exothermic reactions release heat

I am not sure about 16
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Horns are recessive; hornless is dominant. How might this challenge our understanding
wel

Answer:

Please find the explanation below

Explanation:

Traits are physically observed features of an organism. They are coded for and determined by genes, which comes in two forms called ALLELE. Each allele is responsible for a particular phenotype that makes up a trait. A dominant trait is the one which is expressed over another in a heterozygous state i.e. combined state of the two different alleles that encodes the two different traits respectively.

In this question, having horns is a recessive trait while being hornless is a dominant trait. The two traits are encoded by different alleles of the same gene. When the two different alleles combine in the organism's genotype, the dominant trait (hornless) will express itself over its contrasting trait (horn), hence, the animal will be phenotypically hornless. The allele that encodes hornlessness is said to be the dominant allele while hornlessness is the dominant trait.

Note that, in this dominance inheritance pattern, the recessive trait i.e. horned, will only phenotypically be expressed when the recessive allele is homozygous i.e. same in the organism's genotype.

3 0
3 years ago
Consider a mixture of NaCl and NaNO3 that is 31.8% Na by mass. Calculate the percentage by mass of NaCl in the mixture.
lutik1710 [3]

<u>Answer:</u> The percentage by mass of NaCl in the mixture is 38.5 %

<u>Explanation:</u>

To calculate the mass percentage of element in compound, we use the equation:

\text{Mass percent of element}=\frac{\text{Mass of element}}{\text{Mass of compound}}\times 100      .......(1)

  • <u>For NaCl:</u>

Mass of sodium element = 23 g

Mass of NaCl = 58.5 g

Putting values in equation 1, we get:

\text{Mass percent of sodium element}=\frac{23g}{58.5g}\times 100=39.32\%

Mass fraction of sodium metal in NaCl = 0.3932

  • <u>For NaNO_3 :</u>

Mass of sodium element = 23 g

Mass of NaNO_3 = 85 g

Putting values in equation 1, we get:

\text{Mass percent of sodium element}=\frac{23g}{85g}\times 100=27.1\%

Mass fraction of sodium metal in sodium nitrate = 0.271

Let us assume the mass fraction of NaCl in the mixture is 'x'

So, the mass fraction of NaNO_3 in the mixture will be '(1-x)'

We are given:

Percent by mass of Na in the mixture = 31.8 %

Mass fraction of Na in the mixture = 0.318

Evaluating the mass fraction of NaCl in the mixture:

[(x\times 0.3932)+((1-x)\times 0.271)]=0.318

x = 0.385

Percent by mass of NaCl in the mixture will be = (0.385\times 100)=38.5\%

Hence, the percentage by mass of NaCl in the mixture is 38.5 %

4 0
3 years ago
In terms of drug development, rank the following microbes from most difficult (1) to least difficult (3):
iVinArrow [24]

Answer:

See below ↓↓↓

Explanation:

Helminths = 1 Most Difficult

Fungi = 2 Moderately Difficult [Option not given, but 2 is right answer]

Bacteria = 3 Least Difficult

6 0
2 years ago
Science is based on _____.
Korvikt [17]
I think science is based on nature and it's surroundings  <span />
8 0
3 years ago
Read 2 more answers
Which of the following subject areas contains questions that can be answered by science? Alchemy Ethics Forensics Politics
Alika [10]

Answer:

Forensics.

Explanation:

That would be Forensics.  Clues  from a scene of a crime like clothing, blood and so on can be analysed  in the science laboratory , helping to solve the crime.

 Alchemy is not science, nor ethics nor politics.

6 0
4 years ago
Read 2 more answers
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