Chemistry, 08.10.2019 20:00 jamie316

What is the key difference between the chronic and infectious diseases?

a. chronic diseases are contagious, but infectious diseases are not spread between living things.
b. chronic diseases are not contagious, but infectious diseases can be spread between different living things.
c. chronic diseases are more deadly than infectious because they can kill you, but infectious diseases just make you sick and cause disabilities.
d. chronic diseases just make you sick, but infectious diseases are more serious because they can kill you.

which type of pathogen causes diseases like chickenpox and rabies, and cannot be cured?

a. bacteria
b. fungi
c. protozoans
d. viruses

which is a true statement about how germs are spread?

a. animals do not give you germs, only people transfer germs to you.
b. germs can be transmitted between people, animals, or objects.
c. person-to-person contact is required to infect someone with germs.
d. you cannot get germs from something non-living because germs must come from something alive.

ill give 12 points if someone gives me all the right answers ! xdd i know the third one is really easy

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Answer from: Quest

50? i have no !

Answer from: Quest

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.

$m = \frac{moles (solute)}{l ( solution)}$

$1 m = \frac{moles (cacl_{2})}{1 l }= 1 mol cacl_{2}$

let us convert this to grams of cacl₂.

molar mass of cacl2 is 111 g/mol

grams of cacl₂ = $1 mol \times \frac{111g}{mol} = 111 g cacl_{2}$

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 = $\frac{1g}{ml} \times 1000 ml = 1000 g$

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

$molality = \frac{mol (solute)}{kg ( solvent)}$

$molality = \frac{1mol}{0.889kg}$

molality = 1.12 m

step 2 : find boiling point elevation.

the elevation in boiling point is calculated as

$\bigtriangleup t_{b} = i \times k_{b} \times m$

here δtb = boiling point elevation

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

cacl₂ dissociates as $cacl_{2} \rightarrow ca^{2+} + 2 cl^{-}$

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

$\bigtriangleup t_{b} = 3 \times 0.512 \times 1.12$

$\bigtriangleup t_{b} = 1.7$

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

$\bigtriangleup t_{f} = i \times k_{f} \times m$

kf is constant for water and its value is 1.86

$\bigtriangleup t_{f} = 3 \times 1.86 \times 1.12$

$\bigtriangleup t_{f} = 6.2$

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

Answer from: Quest

Change of state has wrong energy change - option 2

brian made this table to organize his notes on changes of state. depostion is a change of state that has the wrong energy change listed. it is utilized to collect data as a portion of the development means and in restricted conditions which may be applied at test.

a deposition in the authority of the united states or research for development in the authority of canada includes the catching of affirmed. the out-of-court verbal assertion of a spectator that may be lessened to a printed record for succeeding application for discovery purposes.

Answer from: Quest

Melting increases as mass increases. since alkanes are not branched molecular structures, the one with the heavier mass will have higher melting point. octane's mp > butane's mp