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2 years ago

13

48 When an atom of the unstable isotope Na-24 decays, it becomes an atom of Mg-24 because the Na-24 atom spontaneously releases(

1) an alpha particle (3) a neutron(2) a beta particle (4) a positron

1 answer:

Crank2 years ago

4 0

(1) a beta particle is your answer. Na-24 decays through beta decay, turning a neutron into a proton, electron (beta particle), and an neutrino.

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A tank contains 200 gallons of water in which 300 grams of salt is dissolved. A brine solution containing 0.4 kilograms of salt

Nadusha1986 [10]

Answer:

<h3>Therefore, after long period of time 80kg of salt will remain in tank</h3>

Explanation:

given amount of salt at time t is A(t)

initial amount of salt =300 gm =0.3kg

=>A(0)=0.3

rate of salt inflow =5*0.4= 2 kg/min

rate of salt out flow =5*A/(200)=A/40

rate of change of salt at time t , dA/dt= rate of salt inflow- ratew of salt outflow

$dA/dt=2-(A/40)\\\\dA=2dt-(A/40)dt\\\\dA+(A/40)dt=2dt$

integrating factor

$=e^{\int\limits (1/40) \, dt}$

integrating factor $=e^{(1/40)t}$

multiply on both sides by $=e^{(1/40)t}$

$dAe^{(1/40)t}+(A/40)e^{(1/40)t} dt =2e^{(1/40)t}t\\\\(Ae^{(1/40)t})=2e^{(1/40)t}t$

integrate on both sides

$\int\limits(Ae^{(1/40)t})=\int\limits2e^{(1/40)t}dt\\\\(Ae^{(1/40)t})=2*40e^{(1/40)t}+C\\\\A=80+(C/e^{(1/40)t})\\\\A(0)=0.3\\\\0.3=80+(C/e^{(1/40)t}^*^0)\\\\0.3=80+(C/1)\\\\C=0.3-80\\\\C=-79.7\\\\A(t)=80-(79.7/e^{(1/40)t})$

b)

after long period of time means t - > ∞

${t \to \infty}\\\\ \lim_{t \to \infty} A_t \\\\ \lim_{t \to \infty} (80)-(79/{e^{(1/40)t}}\\\\=80-(0)\\\\=80$

<h3>Therefore, after long period of time 80kg of salt will remain in tank</h3>

6 0

3 years ago

Work is equal to the what used and multiplyed by the what over which the force was applied

Allushta [10]

W=Fd
Work is equal to the force multiplied by the distance travelled.

4 0

3 years ago

Brenda rode a skateboard 95 meters west. It took her 20 seconds. What was

Artemon [7]

Answer:

D. 4.75 m/s west

Explanation:

You can immediately get the answer once you know the formula for<em> velocity.</em>

The formula for velocity is: Velocity (V) = $\frac{distance (d)}{time (t)}$

The distance is 95 meters while the time is 20 seconds. All you have to do is to divide <u>95 meters by 20 seconds</u>.

Let's solve:

V = $\frac{d}{t}$

V = $\frac{95 meters}{20 seconds}$

V = 4.75 meters per second

Since Brenda is going west with her her skateboard, then you have to add <em>west </em>as her direction.

Brenda's velocity is 4.75 m/s west.

5 0

3 years ago

Draw the structure of the compound formed from propanoic acid and dimethylamine

jeyben [28]

The compound form from propanoic acid and dimethylamine is 3-(dimethylamino)propanoic acid. Propanoic acid is a liquid carboxylic acid that has pungent and unpleasant smell resembling to body odor. Its chemical formula is C2H5C00H. Moreover, dimethylamine is an organic compound and a secondary amine that is colorless, flammable gas with an ammonia like odor. Its chemical formula is (CH3)2NH.

The 2D structure is attached here.

7 0

3 years ago

How many Br atoms are in 1.98 g of Br?

Mkey [24]

Answer:

1.5 x 10²²atoms

Explanation:

Given parameters:

Mass of Br = 1.98g

Unknown:

Number of atoms

Solution:

A mole of a substance is the amount of substance contained in the avogadro's number of particles.

To solve this problem, we must first find the number of moles present in the given mass of the Br atom:

Number of moles = $\frac{mass}{molar mass}$ = $\frac{1.98}{80}$ = 0.025mole.

Now we know that:

1 mole = 6.02 x 10²³

0.025 mole = 0.025 x 6.02 x 10²³ = 1.5 x 10²²atoms

7 0

3 years ago