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lisov135 [29]
3 years ago
10

A radioactive isotope has a half-life of 10 years. What fraction of the original mass will remain unchanged after 50 years

Chemistry
1 answer:
Fofino [41]3 years ago
6 0

The fraction is calculated like this:

\frac{1}{ {2}^{50  \div 10} }  =  \frac{1}{32}

If you want an universal equation for all problems like this:

\frac{1}{ {2}^{time \div halflife} }

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What is the sum of the coefficients when the equation is balanced with the smallest whole numbers? __BaCl2 + __Fe2(SO4)3 → __FeC
aliina [53]

Explanation:

Hphphphphphphphohoohohhpph

8 0
3 years ago
A particular atom contains 29 electrons, 34 neutrons, and 29 protons. what is the identity of this element and what is its atomi
IgorLugansk [536]

Answer:

             Identity =  Copper

             Atomic Number =  29

Explanation:

Given Data:

Number of Electrons  =  29

Number of Neutrons =  34

Number of Protons  =  29

Identity and atomic number of Element:

                              This element can be identified by using two sources, i) Atomic Number ii) Electronic Configuration.

Atomic Number is defined as the number of protons present in the nucleus of an element. As the given number of protons are 29, therefore, the atomic number of this element is also 29.

Secondly, if the element is in neutral state then its number of protons must be equal to the number of electrons present in it. So, in neutral state this element will contain 29 electrons. Therefore, the electronic configuration is as follow,

                                     1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁹

Now using electronic configuration one can easily identify the position of this element in periodic table. As the valence shell is 4, so it belongs to period 4 and there are 9 electrons in d-subshell so it belongs to transition elemnts and transition element with 9 electrons in d shell is Copper. Also, the stable electronic configuration of copper is written as,

                                     1s², 2s², 2p⁶, 3s², 3p⁶, 4s¹, 3d¹⁰

5 0
3 years ago
The average propane cylinder for a residential grill holds approximately 18 kg of propane. how much energy (in kj) is released b
Angelina_Jolie [31]
Let's begin with the basic values  that will be used in the solution.

The formula of propane is C3H8. It is an alkane, a hydrocarbon with the general formula of CnH2n+2. Notice that hydrocarbons have only Carbon and Hydrogen atoms. Its molar mass (M) is 44 g.

Molar Mass Calculation is done as like that
C=12 g/mol, H=1 g/mol. 1 mole propane has 3 moles Carbon atoms and 8 mole Hydrogen atoms. M(
C3H8)= 3*12+ 8*1= 44 g

Combustion reaction of hydrocarbons gives carbon dioxide and water by releasing energy. That energy is called as enthalpy of combustion (
ΔHc°).  

ΔHc° of propane equals -2202.0 kj/mol. Burning of 1 mole C3H8 releases 2202 kj energy. Minus sign only indicates that the energy is given out ( an exothermic reaction ).

Let's write the combustion reaction.
C3H8 + O2 ---> CO2 + H20 (unbalanced) 
ΔHc° = -2202 kj/mol

Now, we calculate mole of 20 kg propane. Convert kilogram into gram since we use molar mass is defined in grams.
mole=mass/molar mass ; n=m/M ; n= 20000 g /44 (g/mol)=454 mole

1 mole propane releases 2202 kj energy.
454 mole propane release 2202 kj *454= 1000909 kj

The answer is 1000909 kj.



6 0
4 years ago
What do holes in volcanic rock illustrate about the conditions in which it was formed?
Sati [7]
Obliviously not all rocks have holes in them
It is called vesicular texture These refers to viscles holes pores or cavities within the igneous rock.the vesicles are the result of gas expansion(bubbles).which often occur during volcanic eruptions .
4 0
3 years ago
Why is nicotine so harmful?
Vikki [24]

Answer:

It lead to diseases like lung cancer

Explanation:

6 0
3 years ago
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