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Valentin [98]
3 years ago
8

2. The heat energy fequired to change a

Chemistry
1 answer:
emmasim [6.3K]3 years ago
8 0
Heat of solution (I believe)
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scandium47 has a half-life of 35s. suppose you have a 45g sample of scadium 47 how much of the sample remains unchanged after 14
Mars2501 [29]

 The much  of the sample that would remain  unchanged  after 140 seconds is 2.813 g

Explanation

Half life  is time taken for the quantity  to reduce  to half its original value.

if the half life  for Scandium  is 35 sec, then the number  of half life in 140 seconds

=140 sec/ 35 s = 4 half life

Therefore 45 g after first half life = 45 x1/2 =22.5 g

               22.5 g after second half life = 22.5 x 1/2 =11.25 g

            11.25 g after third half life = 11.25 x 1/2 = 5.625 g

             5.625 after  fourth half life = 5.625 x 1/2 = 2.813

therefore 2.813 g  of Scandium 47 remains  unchanged.

4 0
3 years ago
a patient is to receive 25 mg of methimazole, a drug used to treat hyperthyroid conditions. the drug is dissolved in solution co
Rainbow [258]
The drug has a concentration of 6 mg per 1 ml. Therefore, to know that number of ml containing 25 grams, we will simply do cross multiplication as follows:
amount of drug = (25 x 1) / 6 = 4.1667 ml

Therefore, for the patient to receive 25 mg of methimazole, he/she should take 4.1667 ml of the drug solution.
8 0
3 years ago
What can you infer about arid climates from their name?
gayaneshka [121]
The receive very little rainfall
7 0
3 years ago
A saturated solution is made by dissolving 0.327 g of a polypeptide (a substance formed by joining together in a chainlike fashi
faust18 [17]

Answer: The approximate molecular mass of the polypeptide is 856 g/mol

Explanation:

To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

\pi=iMRT

Or,

\pi=i\times \frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution in L)}}\times RT

where,

\pi = osmotic pressure of the solution = 4.19 torr

i = Van't hoff factor = 1 (for non-electrolytes)

Mass of solute (polypeptide) = 0.327 g

Volume of solution = 1.70 L

R = Gas constant = 62.364\text{ L.torr }mol^{-1}K^{-1}

T = temperature of the solution = 26^oC=[273+26]K=299K

Putting values in above equation, we get:

4.19torr=1\times \frac{0.327}{\text{Molar mass of solute}\times 1.70}\times 62.364\text{ L.mmHg }mol^{-1}K^{-1}\times 299K\\\\\text{molar mass of solute}=856g/mol

Hence, the molar mass of the polypeptide is 856 g/mol

8 0
3 years ago
How many moles are in 213 mg of calcium fluoride, CaF2?
lana [24]

Answer:

2.73

Explanation:

2.72815277835894

i used an online converter lol it is much faster. if you'd like a step by step guide comment and ill give you one :)

7 0
2 years ago
Read 2 more answers
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