help please
If you have 100 grams of a radioactive isotope with a half-life of 10 years:
part a: How much of the isotope will you have left after 10 years?
part b: How much of the isotope will you have left after 20 years?
part c: How many half-lives will occur in 40 years?

Answer:

the answer is A

Explanation:

Hopefully u get the answer right

Answer:

A

Explanation:

give me thanks not stars

Answer:

21091mg of aspirin the person need to consume

Explanation:

To solve this question we must find the mass of the person in kg. Knowing the lethal dose for aspirin is 400mg/kg of person, we can find the amount of aspirin that the person need to consume to get a lethal dose:

Mass person:

116lb * (1kg / 2.2lb) = 52.7kg

Lethal dose:

52.7kg * (400mg / kg) =

Answer:

Plant breeding

Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals.

Explanation:

Answer:

7.9

Explanation:

pH=-log([H+])

pH=-log(7.7×10⁻⁷M)

pH=6.113509275

Now, poH + pH = 14

Making poH the subject,

poH=14-pH

poH=14-6.113509275

poH=7.886490725

       ≈7.9

∴poH≈7.9

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

Answer:

PH scale is a universal indicator of strongness of base and acid

Answer:

Expof HCl are required to produce 7.50 moles of ZnCl2? 6. Copper ... When 9.34 g of zinc react with excess hydrochloric acid how many grams of zinc chloride will.lanation:

Answer:

55mL

Explanation:

44g / 0.8g/mL = 55mL

Answer:If an atom loses or gains a proton, it becomes a new element. For example, if a sodium atom loses a proton, it would become a negative ion of neon. ... In nuclear reactions, like nuclear fusion, the electrons play minor roles and it is the nucleons that interact to create new elements

Explanation:

Answer:

If an atom loses or gains a proton, it becomes a new element. For example, if a sodium atom loses a proton, it would become a negative ion of neon. ... In nuclear reactions, like nuclear fusion, the electrons play minor roles and it is the nucleons that interact to create new elements.

Explanation:

hope this helps!

Answer:

multiple things.

Explanation:

DNA evidence collected from a crime scene can be linked to a suspect or can eliminate a suspect from suspicion. During a sexual assault, for example, biological evidence such as hair, skin cells, semen, or blood can be left on the victim's body or other parts of the crime scene.

Answer:

I think it is just a

Explanation:

Answer:

The tendency for water molecules to stick together causes it to causes spheres in space. ... Magnetic-like molecules on water's surface cause the surface to behave like an elastic skin. Each molecule is pulled with equal tension by its neighbors.J

Explanation:

the answer to this question is yes

Answer:

68755566

Explanation:elona ouna SEI NOA GOSSTA MAI EPA NOI GESTA

Answer: Energy = 10000J - 2000J = 8000J

Therefore, the energy is dissipated the skier moves down to the slope is 8000J

Explanation:

Answer:

The chemical elements are arranged in order of increasing atomic number. The horizontal rows are called periods and the vertical columns are called groups. Elements in the same group have similar chemical properties. This is because they have the same number of outer electrons and the same valency.

Answer:

pH = 10.75

Explanation:

To solve this problem, we must find the molarity of [OH⁻]. With the molarity we can find the pOH = -log[OH⁻]

Using the equation:

pH = 14 - pOH

We can find the pH of the solution.

The molarity of Ca(OH)₂ is 2.8x10⁻⁴M, as there are 2 moles of OH⁻ in 1 mole of Ca(OH)₂, the molarity of [OH⁻] is 2*2.8x10⁻⁴M = 5.6x10⁻⁴M

pOH is

pOH = -log 5.6x10⁻⁴M

pOH = 3.25

pH = 14-pOH

Answer:

Now, the molar solubility of lead(II) phosphate in water is said to be equal to 6.2⋅10−12mol L−1 . This means that in one liter of water, presumably at room temperature, you can only hope to dissolve 6.2⋅10−12 moles of lead(II) phosphate.

Explanation:

Hope this helps!!

The number of moles of iron (Fe) required to react with 3.82 moles of oxygen is 5.09 moles

3O₂ + 4Fe —> 2Fe₂O₃

From the balanced equation above,

3 moles of O₂ reacted with 4 moles of Fe

From the balanced equation above,

3 moles of O₂ reacted with 4 moles of Fe

Therefore,

3.82 moles of O₂ will react with = (3.82 × 4) /  3 = 5.09 moles of Fe

Thus, 5.09 moles of Fe is needed for the reaction

Learn more about stoichiometry:

https://brainly.com/question/14735801

Answer:

163.940671 grams

Explanation:

You can view more details on each measurement unit: molecular weight of Na3PO4 or grams This compound is also known as Trisodium Phosphate. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Na3PO4, or 163.940671 grams.

Answer:

combustion is fast and destructive it also involves a lot of movement of the atoms where erosion is a slow process that does not involve a lot of energy

Answer:

tetrahedral

As carbon has no 4 valence electrons that are occupied by 4 chlorine atoms, we get 0 lone pair in carbon and sp3 hybridisation which leads to tetrahedral shape.

Answer:

Option A, describes the endothermic reaction represented by this  graph

Explanation:

In this graph the energy released (or the potential energy) at the time of product formation is lower than the potential energy of the reactants. Hence, additional energy input will be required to form the product. Thus, energy is absorbed during the reaction.

Option A is correct

Answer: energy is given off by the reaction

Explanation:

Answer: I go search some information

Explanation:I come back with a answer

Answer: 44.0095.

Explanation:

Answer:

1.25 mL/s

Explanation:

Your are told that 25.0 mL of H2 was produced 20 seconds. This is equal to rate 25/20 = 1.25 mL/s

When a reaction progresses, the reactant concentration gradually decreases and the product concentration gradually increases. Here the rate of the reaction is 1.25 mL/s.

The rate of a chemical reaction is defined as the rate of decrease of concentration of a reactant or the rate of increase of concentration of a product. The rate of the reaction is usually expressed in units mol L⁻¹s⁻¹. The rate of the reaction are affected by several factors like concentration of the reactants, temperature, etc.

An equation which expresses the experimentally observed rate of a reaction in terms of the molar concentration of the reactants which determine the rate of the reaction is called rate equation.

Here it is seen that 25.0 mL of H2 was produced 20 seconds. So the rate is given as:

Rate = 25/20 = 1.25 mL/s

Thus the rate of the reaction is 1.25 mL/s.

To know more about rate of reaction, visit;

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