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AleksandrR [38]
3 years ago
14

PLEASE HELP this is physical science.

Chemistry
1 answer:
Andru [333]3 years ago
6 0

Bone age : 22,920 years

<h3>Further explanation</h3>

Given

Nt = 2.5 g C-14

No = 40 g

half-life = 5730 years

Required

time of decay

Solution

General formulas used in decay:  

\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}

t = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

Input the value :

\tt 2.5=40.\dfrac{1}{2}^{t/5730}\\\\\dfrac{2.5}{40}=\dfrac{1}{2}^{t/5730}\\\\(\dfrac{1}{2})^4=\dfrac{1}{2}^{t/5730}\\\\4=t/5730\rightarrow t=22920~years

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A gaseous fuel mixture stored at 747 mmHg and 298 K contains only methane (CH4) and propane (C3H8). When 11.1 L of this fuel mix
Alisiya [41]

Answer:

M_f=38.8\%

Explanation:

From the question we are told that:

Pressure P=747mmHg

Temperature T=298K

Volume V=11.1

Heat Produced Q=780kJ

Generally the equation for ideal gas is mathematically given by

 PV=nRT

 n= (747/760) *11.1/ (0.0821*298)

 n=0.446mol

Therefore

 x+y=0.446

 x=0.446-y .....1

Since

Heat of combustion of Methane=889 kJ/mol

Heat of combustion of Propane=2220 kJ/mol

Therefore

 x(889) + y(2220) = 760 ...... 2

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 x=0.446-y .....1

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 x=0.173

 y=0.273

Therefore

Mole fraction 0f Methane is mathematically given as

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 M_f=38.8\%

7 0
3 years ago
PLEASE HELP NEED THIS TO PASS!!!
nadya68 [22]

(1)

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(2)

Point F

This is because the solid water stops rising in temperatures and begins changing phase into liquid water. This is the highest temperatures that the solid water can attain without turning into liquid. You can see from the graph that the temperatures rise at this point levels off between point F and G  

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Point H

This is because the liquid water stops rising in temperatures and begins changing phase into gaseous form. This is the highest temperatures that the liquid water can attain without turning into gas/water vapor. You can see from the graph that the temperatures rise  at this point levels off between point H and I.

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The energy is increasing

You can see from the graph that energy is being absorbed by the water (due to increases in energy on the x-axis on the graph) but there is no corresponding rise in temperatures in y-axis. This means the energy begin absorbed is being used to change the phase of the water.

(5)

The water is changing phases

Because the energy absorbed is being used to change the phase of the liquid. The energy is being used to break the bonds between the molecules so the molecules become farther apart and causing a change in phase on the water. Therefore the vibrational moments of the molecules (responsible for rising in temperatures) remain the same over this latent phase. This energy absorbed to change phase is called latent energy/heat.  

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What elements are found in salt?
devlian [24]
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8 0
3 years ago
Cobalt-63 has a half-life of 5.3 years. If a pellet that has been in storage for 15.9 years contains 40.0g of Cobalt-63, how muc
Cerrena [4.2K]

Answer:

320 g  

Step-by-step explanation:

The half-life of Co-63 (5.3 yr) is the time it takes for half of it to decay.  

After one half-life, half (50 %) of the original amount will remain.  

After a second half-life, half of that amount (25 %) will remain, and so on.  

We can construct a table as follows:  

  No. of               Fraction         Mass

half-lives   t/yr   Remaining   Remaining/g

      0        0              1

      1         5.3           ½

     2        10.6           ¼

     3        15.9           ⅛                 40.0

     4        21.2           ¹/₁₆

We see that 40.0 g remain after three half-lives.

This is one-eighth of the original mass.

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5 0
3 years ago
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