1. Which number is more accurate if the correct number is 3.5. Is it 3.1, 3.3, 3.6, or 4.0?

Answer: 0.5g/ml

Explanation:

The density of a substance is given by the following formular; Mass / Volume,

Where mass = 10g

           volume = 20ml

Density = 10g/ 20ml = 0.5g/ml

Answer:

1.7x10^8 Hz

Explanation:

Frequency could be explained as the number of occurrences of a repeating event at a time

Given:

wavelength = 1.8 meters

The frequency f of the waves can be calculated using f = c / λ

Where c (m/s) is the speed of the wave

λ (m) is the wavelength

Speed c= 3*10^8 m/s

Frequency f= 3*10^8 /1.8

Frequency= 1.7x10^8 Hz

Therefore,the frequency of waves from a radar detector is 1.7x10^8 Hz

Answer:

+2

Explanation:

Answer:

Explanation:

Q1) as we know that moles=given mass/molar mass

     mass of 5 moles of Mg is

mass =moles*molar mass

mass=5*24

mass=120 g

mass of 5 moles of CaCO3 is

mass= moles*molar mass

mass=5*100=500

Q2) number of atoms in 10 g Na

first we need number of moles of sodium

moles =mass/molar mass

moles=10/23=0.43

now we know that moles=number of atoms /avogadro number

for number of atom the formula become

number of atom=moles*avogadro number

number of atom=0.43*6.023*10^23=2.6*10^23

Q3)number of molecule in 10 g of NaCl

again we need number of moles of NaCl

moles=given mass/molar mass

moles=10/58.5=0.17

now number of molecules=moles*avogadro number

number of molecules=0.17*6.023*10^23=1.02*10^23

Q4) avogadro number is the number of particles(atoms,molecules,ions) present in one mole of a substance its value is 6.023*10^23

Q5)Number of atoms in 4g of oxygen

again we need number of moles of oxygen

moles=mass/molar mass

moles=4/16=0.25

now number of atoms=moles*avogadro number

number of atoms=0.25*6.023*10^23 =1.5*10^23

Answer:

It represents the relationship between the distance travelled and time spent as constant or at a stop.

Explanation:

This is because as the line progresses, the time increases the distance should change as well my moving up or down, in a linear equation this relationship is constand but if the line is horizontal though, the distance is not changing despite time passing which means it has come to a stop.

Answer:

1. Cu = +2

2. O = – 2

3. C = +2

4. N = 0

Explanation:

Note:

A. The oxidation state of oxygen is always – 2 except in peroxides where it is – 1.

B. The oxidation state of Hydrogen is always +1 except in metallic hydrides where it is – 1.

Now let us solve the question given above.

1. CuO = 0 (ground state)

Cu + O = 0

O = – 2

Cu + (– 2) = 0

Cu – 2 = 0

Collect like terms

Cu = 0 + 2

Cu = +2

2. H2O = 0 (ground state)

2H + O = 0

H = +1

2(1) + O = 0

2 + O = 0

Collect like terms

O = 0 – 2

O = – 2

3. CO = 0 (ground state)

C + O = 0

O = – 2

C + (– 2) = 0

C – 2 = 0

Collect like terms

C = 0 + 2

C = +2

4. N2 = 0 (ground state)

2N = 0

Divide both side by 2

N = 0/2

N = 0

Answer:

d. why matter exists

Explanation:

The kind of questions that chemistry CANNOT answer is "why matter exists".

In Chemistry, question of how the properties, composition and structure of substances are is answered. Also, the transformations that these substances undergo, and the energy that they release or absorbe during the transformation processes are revealed in chemistry.

Chemistry can answer the question of what forms of matter exists but cannot answer why matter actually exists.

e temperature of a 0.750 L gas sample at 25°C and 2.00 atm is changed to 250°C.

Answer:

The heat generated per gram of sample in calories is 0.87 g

Explanation:

Given that,

A calorimeter made from a can is used to measure the calories in a peanut.

During the experiment, the  measured calories were 35% of the true/accepted value given by references

Suppose, the mass of peanut is 0.4 g and find the

We need to calculate the heat generated per gram of sample in calories

Using formula of heat generated

[tex]q=\dfrac{q_{penut\ calorimeter}}{m_{peanut}}[/tex]

Put the value into the formula

[tex]q=\dfrac{0.35}{0.4}[/tex]

[tex]q=0.87\ g[/tex]

Hence, The heat generated per gram of sample in calories is 0.87 g

Answer:

The answer is

Explanation:

The density of a substance can be found by using the formula

[tex]Density = \frac{mass}{volume} [/tex]

From the question

mass = 837.21 g

volume = 37.00 mL

The density of the substance is

[tex]Density = \frac{837.21}{37} \\ = 22.62729[/tex]

We have the final answer as

Hope this helps you

Answer:

Electrons are found in shells or orbitals that surround the nucleus of an atom. Protons and neutrons are found in the nucleus. They group together in the center of the atom.

Explanation:

I'm not sure if this is correct but I hope this helps.

Answer:

The amount of positive charge in a barium nucleus is approximately 8.972 × 10⁻¹⁸ coulomb

Explanation:

The amount of positive charge there is in a barium nucleus is found as follows;

The atomic number of an element is equal to the number of proton present in the atom

The atomic number of barium = 56 = The number of protons in an atom of barium

The positive charge of a single proton is known as an elementary charge, e, given by the formula, e = F/N[tex]_A[/tex]

Where;

F = Faraday's constant

N[tex]_A[/tex] = The Avogadro's number

Therefore, e = 1.602 176 634 × 10⁻¹⁹ C

Which gives the positive charge, Q, of the protons of a barium nucleus as follows;

Q = Number of protons × e

Q = 1.602176634 × 10⁻¹⁹ × 56 ≈ 8.972 × 10⁻¹⁸ Coulomb  per atom of barium.

The amount of positive charge in a barium nucleus ≈ 8.972 × 10⁻¹⁸ coulomb.

Answer:

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Answer The answer to this question is diesel.

Explanation:

Hi there, hope this helps!

The atomic number is 4.

The atomic number of the given atom is equal to 4.

The atomic number (symbol Z) of a chemical element can be defined as the charge number of an atomic nucleus. For an ordinary atom, the atomic number is equal to the number of protons found in the nucleus of an atom of that element.

The atomic number helps to uniquely identify ordinary chemical elements. In an ordinary uncharged atom or neutral atom, the atomic number of that atom is also equal to the number of electrons.

For a neutral atom, the sum of the atomic number and the neutron number gives the atomic mass. The protons and neutrons have approximately the same mass. Atoms that have the same atomic number but different numbers of neutrons or different mass numbers are known as isotopes.

Given the number of electrons in the atom is 4. Therefore, the atomic number of that atom will be equal to 4.

Learn more about the atomic number, here:

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Answer:

A

Explanation:

Answer:

pretty sure its Scientific laws are statements about observed experimental facts, while theories are explanations of natural phenomena.

The statement that correctly explains the difference between a theory and a scientific law is as follows:

Thus, the correct option is B.

A Scientific theory may be defined as a well-explained fact that is significantly associated with the natural world that has been constructed through the utilization of the scientific method, and which brings together many facts and hypotheses.

A Scientific theory is based on observation. It is proven but still testable in nature in order to derive evidence. It generally does not possess mathematical statements and deductions. Theories are explained on nature as well as natural phenomena.

Scientific law is based on unalterable facts or those facts that remain constant. It is proven as well as contains evidence to support the claim. It definitely possesses mathematical statements and deductions.

Therefore, the correct option for this question is B.

To learn more about Scientific theories, refer to the link:

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Answer:

false

in chemical reaction element doesnot change into another

Explanation:

Answer:

The answer is B. Becomes moldy quickly.

Explanation:

This is the most logical answer out of all of them an I took the test.

Answer:

d= 4.8g/mL

m= 19.2 g

V=m/d

V= 4 mL

Answer:

between 80 to 120

Explanation:

because it would be around 100 but it can't be exact.

Answer:

1.375%

Explanation:

Percent Error = measured value - accepted value/ accepted value x 100

Measured Value: 15.78

Accepted Value: 16.00

Work:

[tex]\frac{15.78-16.00}{16.00}[/tex] * 100

[tex]\frac{-.22}{16}[/tex] * 100 = -1.375

You cannot have a negative percentage. Therefore the answer is 1.375%

Answer:

Hypothesis. Hope this helped! :)

Answer:

The answer is Unreactive.

Explanation:

This is an unreactive atom because it has completely filled out stable electrons in the outer shell.

8 electrons in the outer shell means stable.

A. kilogram is the SI unit used to measure mass of body.

B. litre is the SI unit used to measure volume of substance.

C. meter is the unit used to measure length of body.

D. Kelvin is the unit used to measure temperature of body.

Hence, (B) is the correct answer!

Cheers!

Answer:

1) Yes the density does affect it's melting rate.

Explanation:

Simply because the more rock the more time. For instance an ice cube that is empty inside ( has less density ) will take less to melt. Verses an ice cube that is ice to its inner core ( has more density ) will take more time to melt in the same temperature as the first ice cube.

Answer:

Explanation:

Of course you could do the separation chemically. Dissolve the salt up in water, pass thru a filter, wash the iron filings with ethanol, which would encourage the salt to precipitate from solution.

I do hope I helped you! :)

Answer:

by passing a magnet through the mixture

Explanation:

Answer:

Tellurium

Explanation:

Technetium's position on the periodic table is 43 and Tellurium's is 52