i dont understand please help:))

Answer:

4.97 moles

Explanation:

There are  6.022*10^23 calcium  atoms  in 1 mole of  Ca

2.99*10^24/6.022*10^23

=4.97 moles

Answer:

4.97 mol

Explanation:

Given data:

Number of atoms of Ca = 2.99×10²⁴

Number of moles of Ca = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

2.99×10²⁴  atoms × 1 mol  / 6.022 × 10²³ atoms

0.497×10¹ mol

4.97 mol

Answer:

24g

Explanation:

2×12=24

1mole of Mg react with 2 mooe of O2

D snails, guppies and plants. The community should be diverse and have lots of biodiversity.

Answer:

to

Explanation:

to

Answer:

Condenses at 27.25K.

Freezes at 24.65K.

Explanation:

In order to solve this above question, there is is need to make use of the following equation. The main idea here is to convert degree celsius to Kelvin. Hence,

0°C + 273.15 = 273.15K---------------------(1).

Therefore, we will make use of the above equation (1) and slot in the values for at degree celsius at which it condenses and at degree celsius at which it freezes.

So, we have at temperature at which it condenses:

-245.9°C + 273.15 = 27.25K.

Also, we have at temperature at which it freezes.

-248.5°C + 273.15 = 24.65K.

Answer:

Reactants, Activation energy, Energy released by the reaction and Products

Explanation:

This energy profile is that of an exothermic reaction. In an exothermic reaction, heat is liberated to the surrounding. The surrounding becomes hotter than the environment.

The first box to the left is the reactants which signifies the species combining together.

The topmost box is the activation energy which is the energy barrier that must be over come before a reaction takes place.

The box underneath is the energy change. Here, energy is being released.

The right most box is the product of the reaction.

Answer:

CH4

- 4 electron

- 0 electron

- the geometry of Ch4 is tetrahedral

AlF3

- 3 electron

- 0 electron

- the geometry is trigonal planar

CCl4

- 4 electron

- 0 electron

- the geomotry is tetrahedral

SeH2

- 2 electron

- 2 electron

- the geometry is V shape

Answer:

Its a

Explanation:

I got that answer on my own not from the Question ;)

One s-orbital is present in each sublevel of the primary energy level. There are 2 electrons in the s-orbital in total. When compared to other primary energy levels, the electrons in this orbital, known as s electrons, have the lowest energy. Here the correct option is A.

The fixed distances from an atom's nucleus where electrons may be found are referred to as energy levels (also known as electron shells). In an atom, the small, positively charged nucleus is surrounded by smaller, negatively charged electrons.

One s-orbital, three sets of p-orbitals, and five sets of d-orbitals make up the subshell of the third main energy level. S-orbitals can store a maximum of two electrons, p-orbitals six, and d-orbitals ten. One s-orbital is present in each sublevel of the primary energy level. There are 2 electrons in the s-orbital in total.

Thus the correct option is A.

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https://brainly.com/question/9449510

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Answer:

They hatch into larvae.

Explanation:

Answer:

7 hours

Explanation:

627/96=7

7

I hope this helped! :)

Answer:

Yes!

Explanation:

Liquids & gases are poor conductors, but they can make heat (thermal energy) travel quickly from one point to another. ... ~ When waves of heat (thermal energy) travel through empty space and transparent mediums, heat transfer by radiation occurs. Solids, liquids, & gases can all be heated by radiation.

Answer:

I really dont know i just guessed :(

Explanation:

Answer:

index of refraction

Explanation:

Answer:

The sequence of individual steps, or elementary reactions, 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, called the rate-determining step.

Explanation:

Answer:

i think that the answer is B

Explanation:

If a student wants to investigate competition between two organisms in an ecosystem the organisms should have same adaptations and use same resources.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

Learn more about ecosystem,here:

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Answer:4.42×10

​14

​​ x

Explanation:

Answer: Lithium ( 3),Calcium (20),Copper (29),Strontium (38),Potassium (19),Sodium (11)

Explanation:

Answer:

Lithium sulfide

Answer:

Sonoluminescence can occur when a sound wave of sufficient intensity induces a gaseous cavity within a liquid to collapse quickly. [...] The bubbles are very small when they emit the light—about 1 micrometer in diameter—depending on the ambient fluid (e.g., water) and the gas content of the bubble (e.g., atmospheric air).

Explanation:

Source is Google

Answer:

550 K

Explanation:

Given the following data;

Original Volume, V1 = 20mL

Original Temperature, T1 = 200K

New Temperature, V2 = 55mL

To find new temperature T2, we would use Charles' law.

Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.

Mathematically, Charles is given by;

[tex] VT = K[/tex]

[tex] \frac{V1}{T1} = \frac{V2}{T2}[/tex]

Making T2 the subject of formula, we have;

[tex]T_{2} = \frac{V2}{V1} * T_{1}\\[/tex]

Substituting into the equation;

[tex]T_{2} = \frac{55}{20} * 200\\T_{2} = \frac{11000}{20}\\T_{2} = 550K[/tex]

Therefore, the new temperature is 550K.

Answer:

the answer is below

Explanation:

Cirrus clouds form from the ascent of dry air, making the small quantity of water vapour in the air undergo deposition into ice (to change from a gas directly into a solid). Cirrus is made up completely of ice crystals, which provides their white colour and form in a wide range of shapes and sizes.

Answer:

The basic metal ones?

Explanation:

...

Answer:

D

Explanation:

The one that best represents a compound is answer "D" because you compounds are chemically bonded and are always together.

Answer:

The loosening of soil and they bind the soil with the help of the roots

Explanation:

Here, we want to know how plants prevent erosion by wind or water.

The way they do this is by binding the soil with their roots such that it will not be easy for the erosion agent to erode the surface.

How they do this is by making sure that the soil

particles are binded together with their roots which helps to keep the particles of the soil intact and not eroded

Answer:

c

Explanation:

Answer:

0.385 J/g°C

Explanation:

Using the following formula, the specific heat of an elemental substance can be calculated:

Q = m × c × ∆T

Where;

Q = quantity of heat (J)

m = mass (g)

c = specific heat capacity (J/g°C)

∆T = change in temperature (°C)

Based on the given information, Q = 1375J, m = 50g, initial temperature = 22.8°C, final temperature = 94.2°C, c =?

Q = m × c × ∆T

1375 = 50 × c × (94.2 - 22.8°C)

1375 = 50 × c × 71.4

1375 = 3570c

c = 1375/3570

c = 0.3851

c = 0.385 J/g°C

Answer:

wavelength = wave velocity/frequency.

Explanation:

c

 is a constant. It is usually given as

3.00

×

10

8

m/s or

3.00

×

10

10

cm/s rounded to three significant figures.

Wavelength is measured in meters, centimeters, nanometers, etc...).

Frequency has a unit of

1/s

which means

1

cycle per second. It is also given the unit Hertz (Hz) in honor of German physicist Heinrich Hertz who proved the existence of electromagnetic waves.

1

Hz

=

1/s

.

Answer:

flows through your viens and moves to your blood vesils

Explanation:

its how blood operates

Answer: 25 + 27 + 29 = 81

81 divided by 3 = 27

your answer is 27

Explanation: you add them all together then however many numbers there are is how you divide it

Answer:

81 and 27 i think

Explanation:

Answer:

i think iodine

Explanation:

Answer:

5730 years

Explanation: for more on radiocarbon dating.) and hence explain why the amount of carbon-14 in the sample decays by half over any period of 5730 years.