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3 years ago

What is the mass of an original 5.60-gram sample of iron-53 that remains unchanged after 25.53 minutes?

1 answer:

4 0

Answer is 0.7 g

Reason: Given: mass of Fe = 5.60 gWe know that, half life of Fe-53 = t1/2 (Fe-53) = 8.51 min.
Thus, after 25.53 mins, number of half life passed = 25.53/8.51= 3

Now, Amount left after first half life = 5.60g/2 = 2.80 g
Amount left after second half life = 2.80g/2 = 1.40 g
Amount left after third half-life = 1.40g/2 = 0.7g.

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trasher [3.6K]

Answer:

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3 years ago

Rubbing alcohol or isopropanol can be described by the chemical formula C3H7OH. One milliliter of isopropanol has a mass of 0.76

SVETLANKA909090 [29]

A chemical property of isopropanol : D. Isopropanol is flammable.

<h3>Further explanation </h3>

There are changes that occur in the mater: physical changes and chemical changes

Classification uses the principle of the initial and final state of the substance.

Physical changes do not form new substances, so the properties of the particles remain the same.(size,volume,shape)

Example : boiling and freezing, just change its phase form from liquid to gas or from liquid to solid

Chemical changes/reaction form new substances(products) that are different from the initial substances(reactants)

Example : toxic, corroded

So :

the physical properties of isopropanol :

mass, density, evaporation

the chemical properties of isopropanol :

highly flammable

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3 years ago

Read 2 more answers

Pair of substance that have properties entirely different from the atoms that make it up are

MaRussiya [10]

The answer is compounds

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3 years ago

A teacher gives a test to two algebra classes. The first class has 18 students, and the second has 24 students. If the average f

Morgarella [4.7K]

Answer:

The C) statement is true.

Explanation:

Let's call $x_1$ the average for the first class and $x_2$ the average for the second class. The overall average x is then:

$x=\frac{x_1*18+x_2*24}{18+24}\\x=\frac{84*18+x_2*24}{42}\\x=\frac{1512+x_2*24}{42}$

Since the average is given by $Average=\frac{Sum of all values}{Amount of values}$ . We can now calculate x assuming the maximun and minimun values of $x_2$ , 2400 (which is 100 times 24) and 0 respectivly. That gives:

$x=\frac{1512+2400}{42}\\x=93$

for it's maximun value and

$x=\frac{1512+0}{42}\\x=36$

for it's minimun value. So we get that x is between 36% and 93%.

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3 years ago

20 g of Allg is dissolved in water to produce a solution with a concentration of 2.007M. What is the volume of this solution in

Dafna1 [17]

Answer:

369 ml

Explanation:

Mass of Aluminium (Al) = 20 g

Molar concentration = 2.007M

Molar concentration = Number of moles / Volume

The relationship between mass and number of moles;

Number of moles = Mass / Molar mass

Number of moles = 20 / 27 = 0.741 mol

2.007 = 0.741 / Volume

Volume = 0.741 / 2.007 = 0.369 L

converting to millilitres by multiplying by 1000

Volume = 0.369 * 1000 = 369 ml

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3 years ago