The half-life of iodine-131 is about 8 days. How much of a 50mg sample will be left in 25 days? Write your answer rounded to the nearest tenth.

Answer:

(3) 0.70 g

Explanation:

Half life of iron-53 = 8.5167 minutes

[tex]t_{1/2}=\frac {ln\ 2}{k}[/tex]

Where, k is rate constant

So,  

[tex]k=\frac {ln\ 2}{t_{1/2}}[/tex]

[tex]k=\frac{ln\ 2}{8.5167}\ min^{-1}[/tex]

The rate constant, k = 0.08138 min⁻¹

Time = 25.53 minutes

Using integrated rate law for first order kinetics as:

[tex][A_t]=[A_0]e^{-kt}[/tex]

Where,  

[tex][A_t][/tex] is the concentration at time t

[tex][A_0][/tex] is the initial concentration  = 5.60 g

So,  

[tex]\frac{[A_t]}{5.60}=e^{-0.08138\times 25.53}[/tex]

[tex][A_t]=\frac{5.6}{e^{2.0776314}}[/tex]

[tex][A_t]=0.70\ g[/tex]

Answer- (3) 0.70 g

Answer:

After 25.53 minutes there will remain 0.70 grams of the iron-53 sample. Option 3 is correct.

Explanation:

Step 1: Data given

Original mass of the original iron sample = 5.60 grams

Half life of iron-53 = 8.5167 minutes

Step 2: Calculate the rate constant

k = (ln 2)/(t1/2)

⇒ with k = the rate constant

⇒ with t1/2 = the half-life time = 8.5167 minutes

k = 0.08139 / min

Step 3: Calculate the mass after 25.53 minutes

At = A0*e^(-kt)

⇒ with At = the amount of iron sample after 25.53 minutes

⇒ A0 = the initial amount of iron sample =5.50 grams

⇒ with k =  0.08139 / min

⇒ with t = the time = 25.53 minutes

At = 5.50*e^(-0.08139*25.53)

At = 0.70 grams

After 25.53 minutes there will remain 0.70 grams of the iron-53 sample

Answer : The mass of sucrose added to water will be, 189.0 grams.

Explanation :

As we are given that 9 % solution (mass per volume) that means 9 grams of sucrose present in 100 mL volume of solution.

Total given volume of solution = 2.1 L = 2100 mL    (1 L = 1000 mL)

Now we have to determine the mass of sucrose in solution.

As, 100 mL of solution contains 9 grams of sucrose

So, 2100 mL of solution contains [tex]\frac{2100mL}{100mL}\times 9g=189.0[/tex] grams of sucrose

Therefore, the mass of sucrose added to water will be, 189.0 grams.

Answer:

For producing epinephrine , tyrosine is required .

Explanation:

Epinephrine is produced  in  adrenal medulla, where the amino acid tyrosine is transformed to norepinephrine. An enzyme known as phenylethanolamine N-methyltransferase catalyzes the methylation of norepinephrine to epinephrine.

Answer: An increase in the ratio of insulin to glucagon will increase the activity of --

- Acetyl-CoA carboxylase(+)

-Phosphofructokinase PFK2(+)

-Glycogen synthase(+)

- Hormone sensitive lipase (-). The hormone sensitive lipase activity is not increased with increased insulin activity.

Explanation: increased insulin - glucagon ratio is usually high in fed state.Insulin helps the cells absorb glucose, reducing blood sugar and providing the cells with glucose for energy. When blood sugar levels are too low, the pancreas releases glucagon. Glucagon instructs the liver to release stored glucose, which causes blood sugar to rise.

Answer:

Ar atoms in argon gas

Explanation:

Final answer:

Electrostatic forces, including ionic bonds and the strong nuclear force, hold oppositely charged ions, DNA structures, and atomic nuclei together. These forces are central to the integrity and structure of many physical and biological entities.

Explanation:

The electrostatic force is responsible for holding together various types of structures and compounds in physics and chemistry. For example, an ionic bond is an electrostatic attraction that holds ions together in an ionic compound, such as the ion pairs found in salts like sodium chloride (NaCl). The strength of this bond is contingent on the magnitude of the charges and the distance between the ions. For instance, a cation with a 2+ charge will form a stronger ionic bond compared to a cation with a 1+ charge because the electrostatic force increases with larger charges.

Moreover, classical electrostatics plays a crucial role in molecular biology, particularly in the structure of large charged molecules like proteins and DNA. In the case of DNA, which is highly charged, the electrostatic force not only holds the molecule together but also imparts structural integrity and strength to the double helix.

Lastly, within the atomic nucleus, while electrostatic forces cause repulsion between positively charged protons, the strong nuclear force overpowers this repulsion and holds the protons and neutrons together, preventing the nucleus from disintegrating under electrostatic repulsion.

Answer: option C) Na, Mg, K

Explanation:

Similar chemical properties are expressed by elements found in the same or close groups. There are Seven (7) groups in the Periodic table.

Of all the options, ONLY sodium Na, Magnesium Mg, and Potassium K, are located in closely together with SODIUM and MAGNESIUM being in the Same period, while SODIUM and POTASSIUM are placed in the same Group 1.

Therefore, Na, My, and K are most similar in chemical properties

Answer:

O,S,Se

Explanation:

Answer:

Hypothesis

Explanation:

The following steps are applicable when we wish to prove a specific fact:

In the context of this problem, we're at the first step where we make a hypothesis.

Answer:

whats expert verified????

Explanation:

Answer:

The correct option is d, bactericidal

Explanation:

Antimicrobial agent that kill bacteria are called bactericidal and hence, prevents the growth of bacteria.

Antimicrobial agent that slows the growth of the bacteria called bacteriostatic.

Bactericidal and bacteriostatic are types of antibiotics.

Bactericidal antibiotics act by inhibiting cell wall synthesis. Penicillin, cephalosporins, vanomycin, etc are some of bactericidal antibiotics.

Answer:

B. Two chlorine atoms

Explanation:

This electronic configuration shows that the given atom is magnesium.

Electronic configuration of magnesium:

Mg¹² = 1s² 2s² 2p⁶ 3s²

There are two valance electrons of magnesium that's why it would react with two atoms of chlorine. Chlorine is present in seventeen group. It has seven valance electrons. It required just one electron to get complete octet. While magnesium needed to lose two electrons to get complete octet. That's why two chlorine atoms bonded with one magnesium atom. Thus both would get complete octet.

Mg + Cl₂  →   MgCl₂

Answer:The last time levels of atmospheric carbon dioxide were this high came during the Pliocene Epoch, which extended from about 5.3 million to 2.6 million years ago

The amount of nutrients present in the tropic level is called the living state.

The accurate answer is very complicated as the amount of carbon dioxide is changes gradually every day. Therefore the exact date to the same ratio of carbon dioxide is difficult to tell.

In my opinion, the amount of carbon dioxide is high as it if for today is 20 years ago when ozone later starts depleting.

Hence, the correct answer is 20 years ago.

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Answer:

A chemical formula tells us the number of atoms of each element in a compound. It contains the symbols of the atoms of the elements present in the compound as well as how many there are for each element in the form of subscripts.

Explanation:

EXAMPLES:

H2SO4 : Sulfuric Acid. CH4 : Methane.

C12H22O11 : Sucrose. C3H8 : Propane.

NaHCO3 : Baking Soda. F : Fluoride. F2 : Fluoride.

H2O2 : Peroxide.

C8H10N4O2 : Caffeine.

C9H8O4 : Aspirin.

Zn(NO3)2 : Zinc. CO : Carbon Monoxide. NaOH : Sodium Hydroxide. ...

CnH2nOn : Sugar.

Answer:

Amount of CO required is 157.5 g

Explanation:

Molecular mass of Fe = 55.845 g/mol

Amount of Fe = 209.7 g

[tex]Mol\ of\ Fe=\frac{209.7}{55.845} \\=3.75\ mol[/tex]

Balanced reaction of reduction of Fe2O3 is as follows:

[tex]Fe_2O_3(s) + 3CO (g)\rightarrow 2Fe(s)+3CO_2(g)[/tex]

From the balanced reaction, 2 mol of Fe is produced by 3 mol of CO.

Therefore, 3.75 mol of Fe will be produced by,

                                                     [tex]\frac{3}{2} \times 3.75 = 5.625\ mol\ CO[/tex]

Relation between mass and mol is as follows:

Mass = Mol × Molecular formula

Molecular mass of CO = 28 g/mol

Grams of CO required = 5.625 mol × 28 g/mol

                                      = 157.5 g

Amount of CO required is 157.5 g.

Answer:

There are 157.8 grams of CO needed.

Explanation:

Step 1: Data given

Mass of Fe produced = 209.7 grams

Molar mass of Fe2O3 = 159.69 g/mol

Molar mass of Fe = 55.845 g/mol

Step 2: The balanced equation

3CO + Fe2O3 → 2Fe + 3CO2

Step 3: Calculate Moles of Fe

Moles Fe = mass Fe / molar mass Fe

Moles Fe = 209.7 grams / 55.845 g/mol

Moles Fe = 3.755 moles

Step 4: Calculate moles of CO

For 3 moles of CO we need 1 mol of Fe2O3 to produce 2 moles Fe and 3 moles of CO2

For 3.755 moles of Fe we need  3.755 *3/2 = 5.6325 moles of CO

Step 5: Calculate mass of CO

Mass CO = moles CO * molar mass CO

Mass CO = 5.6325 * 28.01 g/mol

Mass CO = 157.8 grams

There are 157.8 grams of CO needed.

Answer: Mass of H2 liberated = 0.039g;

Mass of NaH that reacted = 0.468g

Note: This is the complete question (Binary compounds of alkali metals and hydrogen react with water to liberate H2(g). The H2 from the reaction of a sample of NaH with an excess of water fills a volume of 0.510 L above the water. The temperature of the gas is 35 ∘C and the total pressure is 755mmHg . Find the mass of H2 liberated and the mass of NaH that reacted.)

Explanation:

The equation of the reaction is NaH + H2O ---> NaOH + H2O

molar mass of NaH = 24g, molar mass of H2 = 2g

First, The volume, V1, of the gas produced at standard conditions (s.t.p.) is determined using the general gas equation; P1V1/T1 = P2V2/T2

Making V1 subject of the formula; V1 = P2V2T1/P1T2

P1 = 760mHg, P2 = 755mmHg, V1 = ?, V2 = 0.5L, T1 = 0∘C  = 273K, T2 = 35 ∘C = 308K

V1 = 755*0.5*273/(760*308) = 0.44L

1 mole or 22.4L of H2 has a mass of 2g;

mass of 0.44L of H2 = 2*0.44/22.4 = 0.039g

From the equation of the reaction, 2g of H2 is produced by 24g of NaH at s.t. p.

0.039g of H2 will be produced by 0.039*24/2 = 0.468g of NaH

Answer:

B. produces H⁺ in solution.

Explanation:

Arrhenius theory:-

The Arrhenius theory was introduced introduced by Swedish scientist named Svante Arrhenius in 1887.

According to the theory, acids are the substances which dissociate in the aqueous medium to produce electrically charged atoms ( may be molecule). Out of these species furnished, one must be a proton or the hydrogen ion, [tex]H^+[/tex].

Base are the substances which dissociate in the aqueous medium to produce electrically charged atoms ( may be molecule). Out of these species furnished, one must be a hydroxide ion, [tex]OH^-[/tex].

Hence, the correct option is:- B. produces H⁺ in solution.

According to Arrhenius's theory, an acid is described as B. produces H⁺ in solution.

Arrhenius defined acids as substances that, when dissolved in water, increase the concentration of hydrogen ions (H⁺) in the solution. This definition is based on the idea that acids dissociate in water to release H⁺ ions, which then combine with water molecules to form hydronium ions (H₃O⁺).

For example, when hydrochloric acid (HCl) is dissolved in water, it dissociates into H⁺ and Cl⁻ ions. The H⁺ ions increase the acidity of the solution. This characteristic is central to the Arrhenius definition of acids, distinguishing them from bases, which are defined by their ability to produce OH⁻ ions in solution.

While other definitions of acids, such as Brønsted-Lowry, describe acids as proton donors, Arrhenius specifically focuses on the increase of H⁺ ions in aqueous solutions.

Answer:

Correct answer - B

Explanation:

Radioactive decay is the process of in which an unstable atomic nucleus loses energy by emitting ionize particles and radiation transforming the parent nuclide atom into a different atom called daughter nuclide.

Nuclear equation that show the atomic number and mass number of every particle which are involved in the radioactive decay.

The given  nuclear reaction is as follows.

[tex]^{11}_{6}C\rightarrow ^{11}_{5}B+^{0}_{1}e[/tex]

Therefore,Correct answer - B

Balancing the chemical equation CH₄ + O₂ → CO₂ + H₂O involves making sure that the number of atoms for each element is the same on both sides of the equation. The balanced equation is CH₄ + 2O₂ → CO₂ + 2H₂O.

To balance the given chemical equation CH₄ + O₂ → CO₂ + H₂O, start by looking at the number of atoms of each type on both sides of the equation. In the case of methane (CH₄), there is one carbon (C) atom and four hydrogen (H) atoms. On the product side, we have one carbon and two hydrogens in water (H2O), and one carbon in carbon dioxide (CO₂). Two waters must be produced to balance the hydrogen on both sides. This alteration however, affects the oxygen balance. Now, there are two oxygen atoms in CO₂ and one in H₂O (total of 4) on the product side. Hence, there should be 2 O₂ molecules on the reactant side. The balanced equation is thus CH₄ + 2O₂ → CO₂ + 2H₂O.

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The balanced equation is CH₄ + 2 O₂ → CO₂ + 2 H₂O.

To balance the chemical equation CH₄ + O₂ → CO₂ + H₂O, follow these steps:

The balanced chemical equation is CH₄ + 2 O₂ → CO₂ + 2 H₂O. Remember, it’s crucial not to alter the chemical formulas, only the coefficients in front of them to balance the equation.

Answer:

The order of this half-life reaction is zero. This is a zero order reaction.

Explanation:

Step 1: Data given

At the pressure P0,1 of 55.5 kPa, the half-life is 340 s

At the pressure P0,2 of 28.9 kPa, the half-life is 178 s

Step 2: Calculate the order

(n-1) = ((log (t1/2P0,1 / t1/2P0,2)) / (log (P0,2 /P0,1)))

⇒ with t1/2P0,1 = the half-life at a pressure of 55.5 kPa = 340 s

⇒ with t1/2P0,2 = the half-life at a pressure of 28.9 kPa = 178 s

⇒ with P0,1 = the pressure of 55.5 kPa

⇒ with P0,2 = the pressure of 28.9 kPa

(n-1) = (log (340/178)) /  log( 28.9/55.5)

(n-1) = log (1.91) / log(0.52)

(n-1) = 0.281 / -0.284

n-1 = -1

n = 0

The order of this half-life reaction is zero. This is a zero order reaction.

Answer:

With the appropriate security measures nuclear power, as well as other energy sources, can be used safely.

Explanation:

Nuclear energy, as well as other energy sources, can be dangerous if we do not take the appropriate prevention and protection measures. Nuclear power has one of the lowest levels of fatalities per unit of energy generated, as well as low levels of air pollution-related deaths and allows the reduction of carbon dioxide emissions compared to other energy sources. Since its commercialization, in the 70s, the number of nuclear power accidents is very low compared to the number of accidents of other energy sources, having that coal mining is the most dangerous energy activity in history.

I think that without the correct security considerations, all the energy sources can be dangerous, but if we take security measures as using protection barriers, controlling the reactivity of nuclear power plant, making regularly quality and prevention test control, as well as other measures, we can have the benefits of the nuclear power without worrying too much for danger.      

Therefore, with the appropriate security measures nuclear power, as well as other energy activities, can be used safely.  

I hope it helps you!

Answer:

Rafter also called roof joist.

Explanation:

In roof framing, a rafter serves as the structural member that supports the building's roof. It is part of a rigid structure that is essential for the stability of the roof. Historically, other elements like engaged columns and buttresses were also used to support and stabilize the building structure.

With roof framing, a rafter is a structural member that supports the roof of a building. A rafter is part of a rigid structure formed of relatively slender pieces, which are typically joined together to support the roof. This is critical in roofing as it helps distribute the weight of the roof and ensures the stability of the building.

The history of roof construction shows that the types of construction varied based on the available natural materials. Load-bearing walls played a vital role in supporting the roofs and had to be constructed strong enough not only to support themselves but also the roof. If the roof span was too large, the walls could be pushed out and collapse.

Explanation:

An Element is one and a compound is more than 2elements

Answer:

The difference between an element and a compound is that an element is a substance made of same type of atoms, whereas a compound is made of different elements in definite proportions. Examples of elements include iron, copper, hydrogen and oxygen. Examples of compounds include water (H2O) and salt (Sodium Chloride - NaCl)

Explanation:

Further Differences:

Defintion:

Compound - A compound contains atoms of different elements chemically combined together in a fixed ratio.

Element - An element is a pure chemical substance made of same type of atom.

Representation:

Compound - A compound is represented using its chemical formula that represents the symbols of its constituent elements and the number of atoms of each element in one molecule of the compound.

Element - An element is represented using symbols.

Composition:

Compound - Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds. They contain only one type of molecule. Elements that compose the compound are chemically combined.

Element - Elements contain only one type of atom. Each atom has the same atomic number i.e., the same number of protons in their nucleus.

Answer:metallic bond

Explanation:

The metallic bond consists of a layer of valence electrons electrostatically attracted to positive metal ions. Hence in a metal such as barium, electrons bind the metal ions together in the metallic crystal lattice of the element.

The region associated with electromagnetic spectrum  which contains  light at frequencies and wavelengths that stimulates the rod and cones in the human eye is recognized as the visible region of the electromagnetic spectrum. The eye makes  the association  with some selected portions of that visible region through color.

Energy is inversely proportional to wavelength and it is directly proportional to the frequency.As the frequency and wavelength are related by a constant (c) we can also write the energy in terms of wavelength by the equation  [tex]E = \frac{hc}{\lambda}[/tex].

where h is a Planck's constant,

c is the velocity of the light.

Answer:

14.7 lbs

Explanation:

Air pressure is the weight of the air above us. It is approximately 14.7 pounds or lbs per square inch at sea level. It means that an air column weights 14.7 lbs, 1 square inch in diameter, reaching all the way up to the top of the atmosphere.

Answer:

1.03

I hope it helps you ;)

Answer:

Mass of compound 1 is 0.7144g

Explanation:

1 mole of liposomes =22.4L

20mL (0.02L) of liposomes = 0.02/22.4 = 0.000893mole

Number of moles = Mass/Molecular Weight (MW)

Mass = Number of moles × MW = 0.000893 × 800 = 0.7144g

Answer:

Polychlorinated Biphenyls.

Explanation:

Polychlorinated Biphenyls are man-made chemicals. They are solids, and oily liquid in structure with no taste or small, yellow to clear in color. PCBs are present as a mixture, and very stable at an extreme pressure, and temperature. Basically they are used in electrical equipment such as transformers, and capacitors. High level of PCBs can cause broad spectrum of effects in humans, for example:

1) Increase some liver enzyme level, and cause hepatic damage.

2) Respiratory problems.

3) Dermal lesions.

Answer:

A. 630mL

Explanation:

The combined gas law says:

P₁V₁/T₁ = P₂V₂/T₂

Where P₁ is 2,4 atm; V₁ is 250mL; T₁ is 15+273,15 = 288,15K; P₂ is 1,0 atm; V₂ is the final volume; T₂ is 27°C; 27+273,15 = 300,15K.

Thus:

2,4atm×250mL/288,15K = 1,0atm×V₂/300,15K

V₂ = 625mL ≈ A. 630mL

I hope it helps!

Answer:

[tex]\large \boxed{\text{A. 620mL}}[/tex]

Explanation:

We can use the Combined Gas Laws to solve this problem

Data

p₁ = 2.4 atm;  p₂ = 1.0 atm

V₁ = 250 mL; V₂ = ?

T₁ = 15°C;       T₂ = 27 °C

Calculations

(a) Convert the temperatures to kelvins

T₁ = (15 + 273.15) K = 288.15 K

T₂ = (27 + 273.15) K = 300.15 K

(b) Calculate the new volume

[tex]\begin{array}{rcl}\dfrac{p_{1}V_{1} }{T_{1}} & = & \dfrac{p_{2}V_{2}}{T_{2}}\\\\\dfrac{\text{2.4 atm $\times$ 250 mL}}{\text{288.15 K}} & = & \dfrac{\text{1.0 atm} \times V_{2}}{\text{300.15 K}}\\\\\text{2.08 mL} & = & \dfrac{V_{2}}{300.15}\\\\V_{2} & = & \textbf{620 mL}\\\end{array}\\\text{The volume of the bubble when it reaches the surface is $\large \boxed{\textbf{620 mL}}$}[/tex]

Answer:

Niels Bohr states that the line spectrum of the hydrogen atom by assuming that the electron revolve in circular paths and that the paths  have an allowable radii. ...

Explanation:

discuss the origin of the line citing the bohr theory of the atom specify any energy transitions that are applicable

Niels Bohr states that the line spectrum of the hydrogen atom by assuming that the electron revolve in circular orbits and that orbits have an allowable radii. ... an absorption spectrum is produced, dark lines in the same position as the bright lines in the emission spectrum of an element are produced.

Bohr Atomic Model. Bohr Atomic Model : In 1913 Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus. ... The atom will be stable in the state with the smallest orbit

Bohr explains to us that electron revolve round the nuclues of an atom and possess energy levels. they can change energy levels

Answer:

Depends on the conditions of reaction.

Explanation:

Any element or compound that enters into a chemical reaction can undergoes any process depending of the conditions of reaction, for example, temperature, pressure, medium, among others.

A chemical reaction is a process in which any substance, element or process undergoes chemical and physical changes.

In chemical reaction we have reactants, that is the innitial or starting elements or compounds; products which are the result of the reaction between the reactants and we might see physical changes.

For example, if we do a reaction betwenn Iron and oxygen:

4Fe + 3O2 --------> 2Fe2O3

Iron and oxygen reacts and creates a new product. This is the iron oxyde, which is a physical change too, and you can see that for a color change.

Depending on conditions, we can have several types of chemical reaction, such as synthesis, decomposition, single displacement, double displacement, equilibrium reactions, acid - base reactions among others.

In a chemical reaction, a reactant undergoes a process where it is converted into a product. The sequence of these steps is called the reaction mechanism. The reaction's rate is determined by the rate of the slowest step in the mechanism.

An element or compound that enters into a chemical reaction undergoes a process wherein it is converted into a different substance. This element or compound is called the reactant, and the new substance formed is called the product.

Chemical reactions occur when two or more atoms bond together to form molecules or when bonded atoms are broken apart. The sequence of individual steps by which reactants are converted into products during the course of a reaction is called the reaction mechanism.

The overall rate of a reaction is determined by the rate of the slowest step in its mechanism, called the rate-determining step. Chemical reactions can release or absorb heat, called exothermic and endothermic processes respectively.

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The age of a rock with a mass ratio of argon-40 to potassium-40 of 4.2, and a half-life of potassium-40 of 1.27×109 years, is calculated to be approximately 1.7 billion years old using the potassium-argon dating method.

Calculating Rock Age Using Potassium-Argon Dating

The question asks for the age of a rock, given that the mass ratio of argon-40 (40Ar) to potassium-40 (40K) is 4.2. To find the age of the rock using the potassium-argon dating method, we can apply the concept that 40K decays into 40Ar with a known half-life. This half-life is given as 1.27×109 years.

Using the given mass ratio of 40Ar to 40K, which is 4.2, we can estimate the number of half-lives that have passed. Each half-life passed will result in the remaining 40K being half of what it was before and an increase in 40Ar. We can express the ratio in terms of the decay equation:

NAr / NK = (e−0.693t/T) / (1 − e−0.693t/T)

Where NAr is the amount of 40Ar, NK is the amount of remaining 40K, t is the age of the rock, and T is the half-life of 40K. Solving for t using the given ratio and half-life, we find that the rock is approximately 1.7 billion years old.

Answer:

[tex]_{40}^{103}Zr[/tex]

Explanation:

For any nuclear equation, we should utilize the law of mass conservation and the law of charge conservation. The sum of the masses on the left-hand side of the arrow should be equal to the sum of the masses on the right-hand side of the arrow (those are the superscripts for each nucleus). Similarly, the sums of charges should be equal (this is the law of charge conservation).

Let's say that the missing species is X with a mass of 'M' and charge of 'Z':

[tex]_{94}^{239}Pu+_0^1n\rightarrow _Z^MX+_{54}^{134}Xe+3_0^1n[/tex]

Find mass applying the mass balance law:

[tex]239+1=M+134+3\cdot1\\240 = M+137\\M=240 -137\\M=103[/tex]

This means our particle X has a mass of 103. Let's find the atomic number (the charge) same way:

[tex]94+0=Z+54+3\cdot0\\94=Z+54\\Z=94-54=40[/tex]

The atomic number of our nucleus is 40. That said, we have:

[tex]_{40}^{103}X[/tex]

Find the element in the periodic table with Z = 40. This is Zr. Meaning we can now identify it fully:

[tex]_{40}^{103}Zr[/tex]