Please help me with this question.

Answer:

2.48 g

Explanation:

From the question given above, the following data were obtained:

Original amount (N₀) = 10 g

Time (t) = 1407.6 million years

Amount remaining (N) =?

Next, we shall determine the rate of decay (K) of uranium-235. This can be obtained as follow:

NOTE: Uranium-235 has a half life of 700 million years.

Decay constant (K) =?

Half life (t½) = 700 million years

K = 0.693/t½

K = 0.693/700

K = 9.9×10¯⁴ / year

Therefore, Uranium-235 decay at a rate of 9.9×10¯⁴ / year.

Finally, we shall determine the amount of Uranium-235 remaining after 1407.6 million years as follow:

Original amount (N₀) = 10 g

Time (t) = 1407.6 million years

Decay constant (K) = 9.9×10¯⁴ / year

Amount remaining (N) =?

Log (N₀/N) = kt /2.3

Log (10/N) = (9.9×10¯⁴ × 1407.6) /2.3

Log (10/N) = 0.60588

10/N = antilog (0.60588)

10/N = 4.04

Cross multiply

10 = 4.04 × N

Divide both side by 4.04

N = 10/4.04

N = 2.48 g

Therefore, 2.48 g of uranium-235 is remaining after 1407.6 million years.

If you have a 10 gram sample of uranium-235 there would still be uranium-235 after 1407.6 million years - 2.5 grams.

The half-life of U-235 is the time it takes for half the U to decay. We know that U-235 has 703.8 million years as its half-life which means it takes 703.8 million years to half of its initial amount.

We can construct a table as follows:    

No. of                              Fraction        Amount    

half-lives    t/(yr × 10⁶)     remaining    remaining/g    

   1                703.8              ½              10/2 = 5  

   2              1407.6              ¼              10/4 =  2.50    

Thus, the correct answer is - 2.5 grams.

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Answer:

Qualitative

Explanation:

I'm not sure if there was another part to the question, but if you are looking at the color of the sand, that is a qualitative observation.

Answer:

she bought 3  erasers an got two dollars back

Explanation:

Answer:

3,203.2 g

Explanation:

density multiplied by volume gives you the mass, and both cm3 cancel eachother out so you are left with just g.

Answer:

200 cm^3

Explanation:

V = M/D

V = 120g / (0.6g/cm^3)

V = 200 cm^3

In this case, the volume is 200 cm^3.

Density is defined as the mass of a material substance per unit volume. The equation for density is d = M/V, where d stands for density, M for mass, and V for volume. Grams per cubic centimetre are a typical unit of density measurement.

For instance, the density of Earth is 5.51 grammes per cubic centimetre, but the density of water is 1 gramme per cubic centimetre. Kg/m3 is another way to measure density (in metre-kilogram-second or SI units). For instance, the air has a density of 1.2 kilogrammes per cubic metre.

Textbooks and manuals provide lists of the densities of common solids, liquids, and gases. The mass of a body may be calculated from its volume using density, and vice versa. The mass is equal to the volume multiplied by the density (M = Vd), whereas the volume is equal to the mass divided by the density (V = M/d).

You may calculate a body's weight by multiplying its mass by the acceleration of gravity, which is typical of more practical significance than its mass. Additionally, there exist tables that indicate the weight of various substances per unit volume; this amount is sometimes referred to as specific weight, weight density, or unit weight.

Instead of referring to the density of a single particle, the term "particle density" refers to the number of particles per unit volume and is typically written as n.

Therefore, here the volume is 200 cm^3.

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Answer:

Temperature affects the kinetic energy in a gas the most, followed by a comparable liquid, and then a comparable solid. The higher the temperature, the higher the average kinetic energy, but the magnitude of this difference depends on the amount of motion intrinsically present within these phases

Explanation:

I just know lol

Answer:

the answer is 0.00201168 meters per second

DO NOT HESITATE TP ASK FOR FURTHER EXPLANATION.

Answer:

trial 2: 0.74

trial 3: 5.19

I think but the equation for sloving percent error is:

(true value - determined value)/true value * 100

Explanation:

Answer:

Safety Regulations

Explanation:

hope this helps:)

Answer:

Unlike delegated powers, they are not listed specifically, but are guaranteed by the Tenth Amendment: "The powers not delegated to the United States by the Constitution, not prohibited by it to the States, are reserved to the States respectively, or to the people." Some traditional reserved powers include regulating ...

Explanation:

Answer:

2000 km/sec

1km=1000m

2000×1000

2000,000 m/sec

Answer:

The sum of the number of protons and neutrons in an atom is called the Mass number.

Answer:

Conceptual

Explanation:

Answer:

Conceptual

letter B

As a star uses up its hydrogen supply, it changes from the main sequence star to a Giant. Thus, the correct option for this question is D.

A star may be defined as a type of huge celestial body that is generally constructed of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. They are the luminous bodies that are visible in the sky at night.

A giant is a type of star that has utilized its hydrogen supply in its cores and transformed itself into the thermonuclear fusion of hydrogen in the shell that envelops its surroundings.

This creates an outwards force and stimulates fusion that initiates to increase and hence the star can not able to maintain its equilibrium longer.

Therefore, as a star uses up its hydrogen supply, it changes from the main sequence star to a Giant. Thus, the correct option for this question is D.

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Answer:

0.005

Explanation:

I looked it up

Explanation: It's important to understand that "mg" is the abbreviation

for milligrams and "g" is the abbreviation for grams.

To convert 5 milligrams into grams, we first find the conversion factor

for milligrams and grams, which is 1,000 milligrams = 1 gram.

Next, notice that we're going from a smaller unit,

milligrams, to a larger unit, grams, so we divide.

Whenever we go from a smaller unit to a larger unit,

we will divide by the conversion factor.

So we have 5 mg ÷ 1,000.

When dividing by a power of 10, we can count the number of zeroes

in the power of 10 and move the decimal point that many places to the left.

So our answer is 0.005 grams.

Answer:

This question lacks options, but the question can be answered based on knowledge of proton, electron and neutron number. The answer is:

62 Ni2+ particle

Explanation:

Nickel is a chemical element with atomic number 28. This means it has 28 electrons and 28 protons in its neutral atom. However, the isotope of nickel being described in the question has a mass number of 62. The mass number is calculated by adding the proton number with the neutron number. That is;

Mass number = number of protons + number of neutrons

Mass number = 28 + 34

Mass no. = 62

An element with mass number 62, which has lost two electrons to become positively charged (two positive charges) is described in the question. Hence, the particle that best fits this description is positively charged Nickel particle (Ni2+).

Ni2+ has 28 protons, 26 electrons (reduced by 2) and 34 electrons.

Note that, the 2+ charge is as a result of the loss of two electrons, hence, reducing the electron number by 2.

Answer:

3

Explanation:

Answer:

5

Explanation:

because the 0 is Sig because there is a point and other numbers

Answer:

c

Explanation:

Answer:

it is c because its a hard one and you should know what that is and it is a nonmetal even if not exactly its to be slightly

Explanation:

Answer:

1.6cm3

Explanation:

density = mass/volume

15.6g/cm3= 9.75 g/volume

15.6/9.75 = volume

1.6cm3 = volume

Answer:

line graph

Explanation:

The type of graph would be used to display the data is line graph.

Graph is defined as a visual representation, such as a picture or diagram, that shows information or values in a structured way.  The graph's goal is to visually represent numerical data so that it can be quickly, simply, and clearly understood. As a result, graphs are visual displays of data.

Although a graphical display is easier to understand, data can also be presented as a table. For this kind of data, a line graph will be used. This will show more clearly how the temperature of the water fluctuates over the course of two hours. Time is an independent variable, whereas temperature is a dependent variable.

Thus, the type of graph would be used to display the data is line graph.

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Explanation:

When salt is added to ice, salt first dissolves in the film of liquid water that is always present on the surface, thereby lowering the ice's freezing point

please mark as brainliest ,I really need it

112 km is travelled by car in 60 minutes

1 km is travelled by car in 60/112 minutes

56 km is travelled by car in 60/112*56 = 30 minutes  = 0.5 hours

Explanation:

Answer:

lbm/ft³ or psi/ft

Explanation:

The description in the question shows the density to measured is that of gases (upper atmosphere). The density of a gas can be described as the mass of the gas divided by the volume of the gas at a certain temperature and pressure. It's unit can be represented as lbm/ft³ or psi/ft.

NOTE:

"lbm" means "lean body mass" which is a unit for mass or weight and can be described as the pound mass

"psi" means "pound per square inch"; is also a unit for mass or weight

Answer:

Microwatts.

Explanation:

RF + EMF Unit Conversion Charts: Interpreting exposure levels. When measuring Radio Frequencies, the most common units of measurement are microwatts per square meter (µW/m2), microwatts per square centimeter (µW/cm2) and volts per meter (V/m).

Answer:

No units

Explanation:

In Thin Layer Chromatography (TLC), retention factor (Rf value) is found by taking the distance travelled by the spot divided by the distance of the solvent front. Rf value is a ratio of distances hence they have no units.

Mathematical derivation

The distance travelled by the spot is in cm, and that of the solvent front is also in cm. Thus, dividing the two units would give us no units for the Rf value.

What is TLC?

TLC is a technique used for separation and identification. The stationary phase is polar while the solvent is relatively nonpolar. Thus, the less polar substance is more attracted to the solvent (according to the principle of 'like attracts like') and travels further and thus have a higher Rf value.

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Answer:

there are more than 109 different types of atom - one for each element.

Answer: the last one:)

Explanation: energy cannot be destroyed but can be transfered

(called energy transfer).