1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
dolphi86 [110]
2 years ago
12

Element X consist of two isotopes with masses of 62.9 and 64.9. The relative atomic mass of the element is 63.6. What is th

Chemistry
1 answer:
koban [17]2 years ago
4 0

Answer:

it is 50%

Explanation:

62.9x50=3145

64.9x50=3245

3245+3145=6390

6390/100=63.9

You might be interested in
Air containing 0.04% carbon dioxide is pumped into a room whose volume is 6000 ft3. The air is pumped in at a rate of 2000 ft3/m
koban [17]

Here is the full question:

Air containing 0.04% carbon dioxide is pumped into a room whose volume is 6000 ft3. The air is pumped in at a rate of 2000 ft3/min, and the circulated air is then pumped out at the same rate. If there is an initial concentration of 0.2% carbon dioxide, determine the subsequent amount in the room at any time.

What is the concentration at 10 minutes? (Round your answer to three decimal places.

Answer:

0.046 %

Explanation:

The rate-in;

R_{in} = \frac{0.04}{100}*2000

R_{in} = 0.8

The rate-out

R_{out} = \frac{A}{6000}*2000

R_{out} = \frac{A}{3}

We can say that:

\frac{dA}{dt}= 0.8-\frac{A}{3}

where;

A(0)= 0.2% × 6000

A(0)= 0.002 × 6000

A(0)= 12

\frac{dA}{dt} +\frac{A}{3} =0.8

Integration of the above linear equation =

e^{\int\limits \frac {1}{3}dt } = e^{\frac{1}{3}t

so we have:

e^{\frac{1}{3}t}\frac{dA}{dt}} +\frac{1}{3}e^{\frac{1}{3}t}A = 0.8e^{\frac{1}{3}t

\frac{d}{dt}[e^{\frac{1}{3}t}A] = 0.8e^{\frac{1}{3}t

Ae^{\frac{1}{3}t} =2.4e\frac{1}{3}t +C

∴ A(t) = 2.4 +Ce^{-\frac{1}{3}t

Since A(0) = 12

Then;

12 =2.4 + Ce^{-\frac{1}{3}}(0)

C= 12-2.4

C =9.6

Hence;

A(t) = 2.4 +9.6e^{-\frac{t}{3}}

A(0) = 2.4 +9.6e^{-\frac{10}{3}}

A(t) = 2.74

∴ the concentration at 10 minutes is ;

=  \frac{2.74}{6000}*100%

= 0.0456667 %

= 0.046% to three decimal places

7 0
3 years ago
why do you think you can find silver and gold on their own in rocks but calcium and magnesium are combined with other elements t
katrin [286]

Explanation:

Silver and Gold belong to a special group of metals known as the native metals. They are found naturally on their own and not in combined form in rocks.

  • These metals are found uncombined because they are unreactive.
  • They prefer to alloy with themselves.
  • Calcium and magnesium on the other hand are reactive metals.
  • The unreactivity of these metals makes them uncombined in nature.
4 0
3 years ago
Read 2 more answers
The mass of an object is 1,000 g. It has a volume of 100 mL. What is the density of the object? D= mass/volume
maxonik [38]

Answer:

10 g/ml

Explanation:

divide mass by volume means divide 1000 by 100 and your answer will be 10

4 0
3 years ago
Einstein's formula tells us the amount of energy to which a given mass would be equivalent, if it were all suddenly turned into
skad [1K]
Einstein's famous equation, E = mc^2 relates the mass (m) of an object to energy (E). The speed of light (c), is the constant of proportionality. Einstein formulated the equation within his theory of special relativity. Indeed, a physical interpretation of this equation is that any given mass is equivalent to the energy given by the equation, if it were suddenly converted to energy. Therefore the answer to the question is true. 
5 0
3 years ago
Suppose the half-life is 9.0 s for a first order reaction and the reactant concentration is 0.0741 M 50.7 s after the reaction s
bazaltina [42]

<u>Answer:</u> The time taken by the reaction is 84.5 seconds

<u>Explanation:</u>

The equation used to calculate half life for first order kinetics:

k=\frac{0.693}{t_{1/2}}

where,

t_{1/2} = half-life of the reaction = 9.0 s

k = rate constant = ?

Putting values in above equation, we get:

k=\frac{0.693}{9}=0.077s^{-1}

Rate law expression for first order kinetics is given by the equation:

k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}     ......(1)

where,

k = rate constant  = 0.077s^{-1}

t = time taken for decay process = 50.7 sec

[A_o] = initial amount of the reactant = ?

[A] = amount left after decay process =  0.0741 M

Putting values in equation 1, we get:

0.077=\frac{2.303}{50.7}\log\frac{[A_o]}{0.0741}

[A_o]=3.67M

Now, calculating the time taken by using equation 1:

[A]=0.0055M

k=0.077s^{-1}

[A_o]=3.67M

Putting values in equation 1, we get:

0.077=\frac{2.303}{t}\log\frac{3.67}{0.0055}\\\\t=84.5s

Hence, the time taken by the reaction is 84.5 seconds

6 0
3 years ago
Other questions:
  • You make dilutions of curcumin stock solution and measure the absorbance of each dilution to obtain the following data: Conc. (M
    12·1 answer
  • Describe two hazards identified with hydrochloric acid?
    5·1 answer
  • What number would you write before water in the formula for calcium carbonate hexahydrate?  4 5 6 7
    5·1 answer
  • PLEASE HELP ME!!!! Brainiest to the first person to get it right
    8·2 answers
  • Not needed anymore! Sorry for the inconvenience.
    5·1 answer
  • A 40 kg dog is sitting on top of a hillside and has a potential energy of 1,568 J. What is the height of the hillside? (Formula:
    10·1 answer
  • The Bantu were experts in this form of metallurgy. gold steel iron copper
    5·2 answers
  • Which direction will the following reaction (in a 5.0 L flask) proceed if the pressure of CO_2(g) is 1.0 atm? CaCO_3(s) rightarr
    6·1 answer
  • Where does Earth's Internal Energy Come From? *
    12·2 answers
  • An oxide of P contains 50% by mass of P. Its Relative molecular mass is 64. The molecular formula of the oxide is (P=32; O=16)
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!