Part B: Find Credible Sources When designing a scientific research paper, look for the most credible sources. Science does not show bi
humans tend to show bias. Some sites and articles provide facts without proper scientific evidence. Avoic
information from such sites. You must be able to identify reliable sites so the data in your paper is credit
Use sources that end in gov (government sites), such as CDC. gov. They are reliable sources. You can also
in. edu. They can be deemed trustworthy. Sometimes, however, the information on .edu sites is written
rather than scientists. Always find out who the author of the article is before proceeding. Some .org and
credible. However, you need to analyze the contents to verify their authenticity. As you review a source, a
answer these questions:
Who authored the article?
• Is this person a scientific expert in the topic area?
• What is the purpose of the article?
• Does the article state facts that scientists can prove with evidence?
. Are there opinions in the article?
How old is the article?
• Do other credible sources support the statements in this article?
Find some credible websites, and note the information they contain. Write down two or three sources th
your presentation. Cite them using MLA (Modern Language Association) citation methods

plasma - state of matter made up of electrically charged particles

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.

the missing options are :

(1) lower boiling point and a lower freezing point(2) lower boiling point and a higher freezing point(3) higher boiling point and a lower freezing point(4) higher boiling point and a higher freezing point

answer : the correct answer is option (3) higher boiling point and a lower freezing point

explanation :

when a non volatile solute is added to a solvent like water, it results in elevation of boiling point.

let us find the increase in boiling point of water when cacl₂ is added to water to make a solution of 1 m

step 1 : find molality of the solution

let us assume we have 1 l of solution.

let us convert this to grams of cacl₂.

molar mass of cacl2 is 111 g/mol

grams of cacl₂ =

mass of solute = 111 g

assuming density of solution same as water which is 1g/ml we have ,

mass of solution = density * volume

mass of solution =

mass of solution = mass of solvent + mass of solute

mass of solute = 1000g - 111g

mass of solute 889 g = 0.889 kg

the molality of the solution can be calculated as

molality = 1.12 m

step 2 : find boiling point elevation.

the elevation in boiling point is calculated as

here δtb = boiling point elevation

i = vant hoff factor which is the number of ions formed by the solute .

cacl₂ dissociates as

it forms 3 ions . therefore,

i = 3

m = molality which is 1.12 m

kb is constant for a given solvent. for water it is 0.512

the boiling point of water increases by 1.7 °c

step 3: find freezing point depression.

when a non volatile solute is added to water, it results in decrease in freezing point.

the formula to find freezing point depression is

kf is constant for water and its value is 1.86

the freezing point of water decreases by 6.2 °c

therefore we can say that, the solution will have a higher boiling point and a lower freezing point