A radioactive sample is placed in a closed container. Two days later only one-quarter of the sample is still radioactive. What is the half-life of this sample?

Answers

Answer 1

Answer:

2

Explanation:

The sample has halved twice.

1/2 of 1/2 is 1/4, and 1/2 of 1 is 1/2.


Related Questions

Is NaClO4/HClO4 a buffer system

Answers

Answer:

In this type of solution, perchloric acid is a strong acid which means that its conjugate base is extremely weak. As such, the solution of HClO4 H C l O 4 and NaClO4 N a C l O 4 is not a buffer solution.

Identify two ways to measure mass​

Answers

Answer:

Putting it in water, and see the displacement of the water, or just measuring its weight and devide it by the gravitational pull

Scientists use a balance to obtain an object’s mass. A balance compares an object with a known mass to the object in question. One example of a balance is the triple beam balance. The standard unit of measure for mass is based on the metric system and is typically denoted as kilograms or grams.

1. Liver Balance
2. Physical balance
3. Electronic Balance

Water is placed into a sealed jar and has a mass of 22.0 grams. The jar is placed in the freezer and the water turns to ice. The jar of ice is measured. The mass should be:

a. Slightly less than 22.0 grams
b. Exactly 22.0 grams
c. Slightly more than 22.0 grams

Answers

exactly 22.0 grams

because freezing is a physical change not a chemicl change..so nothing is taken away or added

ANSWER;

exactly 22.0 grams

because freezing is a physical change not a chemicl change..so nothing is taken away or added

Phosphorous-32 has a half life of 14.3 days while radon-222 has a half-life of 3.8 days, so phosphorous-32 is considered more active.

a. True
b. False

Answers

The answer is B - False

What is the chemical formula for peracetic acid?

Answers

The chemical formula for peracetic acid is C2H4O3. This means that there are 2 atoms of carbon, 4 atoms of hydrogen, and 3 atoms of oxygen in a single molecule.

I think that the answer is C2H4O3.

The orbit of a planet is an ellipse with the sunat one of the foci.. This is Kepler's........ second law third law first law​

Answers

Answer:

its keplers first law

Explanation:

answer from gauth math

The specific gravity of a vegetable oil is 0.92. What is the massgrams, of 330 mL of vegetable oil?

Answers

Answer:

HOPE THIS ANSWER WILL HELP YOU

The rate of reaction for the decomposition of hydrogen peroxide to yield water and oxygen is given by the equation: Rate = k[H202). Which of the following is indicated by this equation?

a. The rate of the reaction is unaffected by the concentration of H2O2.
b. The rate of the reaction will increase with increasing concentration of H2O2.
c. The rate of the reaction will decrease with increasing concentration of H2O2.
d. None of these

Answers

c. the rate of reaction will decrease with increasing concentration of H2O2 is false

When a liquid is at its boiling point, the vapor pressure of the liquid

Answers

When the liquid is at its boiling point the vapor pressure of the liquid increases

compared to those
5. Electrons farther away from the nucleus in an atom have
closer to the nucleus.
O A. lower energy
OB. higher energy
O C. the same energy
O D. higher or lower energy, depending on the element

Answers

Explanation:

higher or lower energy, depending on the element

Answer:

B

Explanation:

Oceanography does not include the study of which of the following topics?

A.the relationship between the Sun, Moon, and Earth

B.the relationship between the atmosphere, Earth, and the oceans

C.the Earth's oceans

D.the plants and animals that live in the oceans

Answers

Answer:

A. The relationship between the Sun,Moon,and Earth

Explanation:

Hydrochloric acid is used to produce fertilizers and dyes, to pickle and clean metal products, and as a reagent in the photographic and rubber industries. Which of the following is a chemical property of hydrochloric acid?


Liquid hydrochloric acid can vaporize into a gas at 48 degrees Celsius

All of these are chemical properties of hydrochloric acid

Hydrochloric acid is soluble in water

Hydrochloric acid reacts with the materials to produce bubbling, or fizzing, a gas, and heat.

Answers

Answer:

Hydrochloric acid reacts with the materials to produce bubbling, or fizzing, a gas, and heat.

Explanation:

Plllsssss hel pls help

Answers

the answer is A
In approximately 5 billion years, the sun will begin the helium-burning process, turning into a red giant star. When it expands, its outer layers will consume Mercury and Venus, and reach Earth.

A cation of 2 indicates that an element has Group of answer choices lost two neutrons. lost two protons. gained two electrons. lost two electrons. gained two protons.

Answers

Answer:

lost 2 electrons

Explanation:

A cation by definition is a positively charged ion. They are formed when a metal loses its electrons. A cation has more protons than electrons, giving it a net positive charge. So, it had to have lost 2 electrons to give it a positive charge of 2⁺.


In your own words, summarize the contrasting arguments of Democritus and Aristotle about the composition (make up) of matter.

Answers

Answer:

Aristotle disagreed with Democritus and offered his own idea of the composition of matter. According to Aristotle, everything was composed of four elements: earth, air, fire, and water. The theory of Democritus explained things better, but Aristotle was more influential, so his ideas prevailed.

pls mark me as a branlist


* The 'emf generated by
a copper-constantan thermometer is 15 mv. If the cold junction is at a temperature of 20 degrees celcius.Calculate the temperature of the hot junction when sensitivity
of the thermocouple is 0.03mv/degree celcius

Answers

Thermometers are used to measure temperatures. The temperature of the hot junction of the thermocouple is [tex]520^oC[/tex]

Given that:

[tex]EMF = 15mv[/tex]

[tex]T_1 =20^oC[/tex] --- Temperature at cold junction

[tex]s = 0.03mv/^oC[/tex] ---- Sensitivity

The temperature [tex]T_2[/tex] at the hot junction is calculated as follows:

[tex]T_2 = \frac{EMF}{s} + T_1[/tex]

So, we have:

[tex]T_2 = \frac{15mv}{0.03mv/^oC} + 20^oC[/tex]

[tex]T_2 = \frac{15}{0.03/^oC} + 20^oC[/tex]

[tex]T_2 = \frac{15}{0.03}^oC + 20^oC[/tex]

[tex]T_2 = 500^oC + 20^oC[/tex]

[tex]T_2 = 520^oC[/tex]

Hence, the temperature of the hot junction of the thermocouple is [tex]520^oC[/tex]

Read more about thermometers at:

https://brainly.com/question/13271366

a transistor has beta=180 calculate the approximate collector and base currents if the emitter current is 10ma

Answers

Answer:

kausvsnks

Explanation:

bdjwkagsjwlak

How many atoms are in 0.100 mol of C3H8

Answers

number of atoms = mole x Avogadro’s Number

= 0.1 x 6.022 x 10^23
= 6.022 x 10^22

List of choices for questions 20-24: A. (1) CH3MgBr, (2) H3O , (3) CH3MgBr, (4) H3O B. (1) LDA, (2) CH3I, (3) H3O C. (1) CH3MgBr, (2) H3O , (3) NaBH4, (4) H3O D. (1) DIBAH, (2) H3O E. (1) NaOH, heat, (2) SOCl2, (3) CH

Answers

Answer:

h30

Explanation:

aluminum has a density of 2.70 g/mL. Calculate the mass (in grams) of a piece of aluminum having a volume of 344 mL

Answers

Probably 928.8 bc most of the times mass is bigger than volume and density. ( I got it by multiplying density and volume.)

Answer:

[tex]\boxed {\boxed {\sf 928.8 \ grams}}[/tex]

Explanation:

Density is the mass per unit volume of a substance. The following formula is used for calculating density.

[tex]\rho= \frac{m}{v}[/tex]

We know the density of aluminum is 2.70 grams per milliliter. The mass is unknown, but we know the piece of aluminum has a volume of 344 milliliters.

ρ= 2.70 g/mL v= 344 mL

Substitute these values into the formula.

[tex]2.70 \ g/mL = \frac {m}{344 \ mL}[/tex]

We are solving for the mass, so we must isolate the variable m. It is being divided by 344 milliliters. The inverse operation of division is multiplication. Multiply both sides of the equation by 344 mL.

[tex]344 \ mL *2.70 \ g/mL = \frac {m}{344 \ mL} * 344 \ mL[/tex]

[tex]344 \ mL *2.70 \ g/mL =m[/tex]

The units of milliliters cancel.

[tex]344 *2.70 \ g=m[/tex]

[tex]928.8 \ g =m[/tex]

The mass of the piece of aluminum is 928.8 grams.

What is 47.35 dL= mL?

Answers

Answer:

4.735 litres

Explanation:

10 dL = 1 litre

47.35 dL = 47.35/10 = 4.735 litres

how much energy is contained in 3moles of chlorine​

Answers

Answer:

1 mol of cl2 contains 71 g

3 mol of cl2 will contain÷

3×71=213 g

Explanation:

There ;3

Answer:

213 g

Explanation:

multiply 3 moles by relative atomic mass of chlorine which is 35.45×2 because its two chlorines and your answer will be 213g

What are precautions to be taken when doing titrations? A-Make sure to always vigorously shake that flask after every drop if the end point is still unknown. It may be that the remaining volume of the titrant needed to reach the end point is just adhering on the wall. This is to ensure accuracy. B-The amounts of solid and liquid should be weighed and pipetted with high accurac This is because all the data that will be produced will mainly depend on this. C- If the end point is unknown, dropwise addition of the titrant is recommended. D- Always make sure that the indicator is added. E- All of the above​

Answers

Answer:

E

Explanation:

This is because all steps from A-D are important to obtain an accurate result

In rutherfords gold foil experiment, most alphas particles passed through the gold foil without deflection and were detected on the screen. What caused the particles to pass through without any deflection?

Answers

Answer:

The vast majority of the volume in an atom consists of the electron orbitals with electrons that have too little mass to deflect the alpha particles.  So most pass right through the foil.  Only the ones hitting the nucleus are deflected.

Explanation:

The whole reason Rutherford and his students conducted this experiment was to test the then current hypothesis that an atom consists of a homogeneous blend of atomic particles, known as the "plum pudding" model.  If so, there should be no, or minimal, deflection of particles.  That's not what they found.  Since particles were found to be deflected, the group concluded that atoms must contain a large object, which became known as the nucleus.

Please help thank you (15 points)

Answers

Answer:

C.

Explanation:

The arrows represent the Earth spinning on its own axis in this picture.

How many inches are in 1.00 km

Answers

1 kilometer =
39370.079 inches
39370.08 inches in 1 Kilometre hi mom

What is the reducing agent in the redox reaction represented by the following cell notation?
Zn(s) ∣ Zn2+(aq) ∣∣ Ag+(aq) ∣ Ag(s)

Answers

the reducing agent is Zn… reducing agent is the element/compound that undergoes oxidation

To solve such this we must know the concept of redox reaction. Therefore, Zn is the reducing agent represented by the given cell notation

Zn(s) ∣ Zn2+(aq) ∣∣ Ag+(aq) ∣ Ag(s)

What is chemical reaction?

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

Redox reaction is a chemical reaction where oxidation and reduction takes place simultaneously. Oxidation is loss of electrons and reduction is gain of electrons. The electron transfer from oxidant to reductant. Zn is the reducing agent in the given reaction. The component that undergoes oxidation is known as a reducing agent.

Therefore, Zn is the reducing agent in the given reaction.

Learn more about the chemical reactions, here:

brainly.com/question/3461108

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limewater turns cloudy or milk when a gas bubbled through it. what is the cause of its cloudiness?​

Answers

hi <3

the cloudiness is caused by the production of carbon dioxide

hope this helps :)

Answer:

Lime water is calcium hydroxide with formula

[tex]{ \sf{Ca(OH)_2}}[/tex]

when calcium hydroxide reacts with the gas [ carbon dioxide ]

[tex]{ \sf{Ca(OH)_{2(aq)} + CO_{2(g)} → CaCO_{3(s)} + H_2O_{(l)}}}[/tex]

Calcium carbonate is white cloudy precipitate

What is the correct clases for this drugs

‏Compazine
heelp me please
and
Promethazine

Answers

Answer:

Compazine belongs to a class of drugs called Antiemetic Agents; Antipsychotics, Phenothiazine.

why hydrogen has dual nature?​

Answers

Answer:

Since hydrogen has a single electron in its valence shell, it exhibits dual nature. of the periodic table, or it can obtain one electron to complete its valency of two, such as halogens from Group 17. Since it only has one electron in its outer shell, hydrogen has a dual existence.

Explanation:

This means that, like a normal halogen, a hydrogen atom can easily gain an electron to form a complete outer shell, or lose an electron to form an alkali metal. Since it already has two electrons in its outer shell, hydrogen can be diatomic, rendering it unreactive.

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