i need help with this asap for brainly

Answer:

8.36 g

Explanation:

From;

0.693/t1/2 = 2.303/t log (No/N)

t1/2 = half life of potassium-40

t = age of the sample

No= initial amount of the sample

N= amount of the sample at time t

Substituting values;

0.693/1.3 × 10^9 = 2.303/2.6 × 10^9 log (No/2.10)

5.33 × 10^-10 = 8.86 × 10^-10 log (No/2.10)

5.33 × 10^-10/8.86 × 10^-10 = log (No/2.10)

0.6 = log (No/2.10)

Antilog (0.6) = (No/2.10)

No = 2.10 × Antilog (0.6)

No= 8.36 g

ANSWER:

Explaining the experiments on the photoelectric effect. How these experiments led to the idea if light behaving as a particle of energy called a photon.

Answer:

15/16

Explanation:

We need to find the number of moles of hydrogen and number of moles of ethane present.

Since we have the same mass, m for both substances, the number of moles of hydrogen, n = m/M where M = molar mass of hydrogen molecule

Since hydrogen is H₂, M = 2 × 1 g/mol = 2 × 1 g/mol = 2 mol.

n = m/M

n = m/2

Also, number of moles of ethane, n' = m/M' where M' = molar mass of ethane.

Since ethane is C₂H₆, M' = 2 × 12 g/mol + 6 × 1 g/mol = 24 g/mol + 6 g/mol = 30 g/mol

n' = m/M'

n' = m/30

The total number of moles of gas present is thus n" = n + n' = m/2 + m/30 = (15m + m)/30 = 16m/30

The mole fraction of hydrogen is thus number of moles of hydrogen/total number of moles = n/n" = m/2 ÷ 16m/30 = m/2 × 30/16m = 15/16

Also, since the partial pressure due to hydrogen, P = mole fraction × total pressure, P'

P/P' = mole fraction = 15/16

So, The fraction of the total pressure exerted by hydrogen is 15/16

Explanation:

to find POH u need PH first

so ph=-log(h3o)

so

[tex]ph = - log(1 \times {10}^{ - 8} ) \\ \\ ph = 8 \\ ph + poh =14 \\ poh = 14 - 8 \\ poh = 6[/tex]

Answer:

I believe it's a.

Explanation:

Answer:

I think the answer would be b, sorry if I'm wrong(EDIT: ITS ACTUALLY AAAAA)

Answer:

Explanation:

what are the statments i can't help till i have the posable answers

goodnight Gucci chunk cubic DDF if f Ch BK

Answer:

gravity

Explanation:

Gravity is an example of the force of attraction between two objects that have mass.

Answer:

No observable change.

Explanation:

Copper renders dilute sulphuric acid passive, no reaction.

H2SO4+Cu-->CuSO4+H2

Explanation:

THIS IS THE CORRECT ANSWER

Answer:

Decomposition Reaction

Answer:

Coke

Explanation:

A solid fuel formed by heating coal in the absence of air is coke. Coke is black colored, tough porous substance. It is pure carbon.

Vapourization and condensation. the actual 1 shud be vapourization.

Answer:

1. Neutron number = 43

2. Proton number = 34

3. Electron number = 36

Explanation:

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

Mass number = 77

Charge of ion = –2

1. Determination of the number of neutron.

Mass number of Se = 77

Atomic number = 34

Neutron number =?

NOTE: Atomic number = proton number

Mass number = Proton + Neutron

77 = 34 + Neutron

Collect like terms

77 – 34 = Neutron

Neutron number = 43

2. Determination of the proton number.

The atomic number of an element is simply defined as the number of protons in the atom of the element. Mathematically,

Atomic number = Proton number

Atomic number of Se = 34

Therefore, the proton number of Se²¯ is 34.

NOTE: The atomic number does not change be it atom, ion or molecule. It remains the same.

3. Determination of electron number.

Charge of ion = –2

Proton number = 34

Electron number =?

Proton – Electron = Charge

34 – Electron = –2

Rearrange

34 + 2 = Electron

36 = Electron

Electron number = 36

There are 43 neutrons, 34 protons, and 36 electrons in the given selenium ion with a (-2) charge.

Explanation:

Given:

A selenium ion with a mass number of 77  and a charge of (-2).

To find:

The number of neutrons, protons, and electrons in selenium ion

Solution:

Charge on the selenium  ion = -2

The atomic number of selenium = 34

Number of protons = Atomic number

Number of protons in selenium atom = 34

Number of protons in selenium ion = 34

Number of electrons in selenium atom = 34

Number of electrons in selenium ion=  34+2 = 36

(anion is formed by gaining of electrons that is why adding two electrons )

The mass number of selenium = 77

Mass number = Number of protons + Number of neutrons

77 = 34 + Number of neutrons in selenium

Number of neutrons in selenium ion = 77 - 34 = 43

There are 43 neutrons, 34 protons, and 36 electrons in the given selenium ion with a (-2) charge.

Learn more about atoms and ions here:

brainly.com/question/18481428

brainly.com/question/1659592?referrer=searchResults    

Answer:

13924g/mol is the molar mass of the protein

Explanation:

What is the molar mass of the protein.

The osmotic pressure of a solution, π, is defined as:

π = c*R*T

Where π is osmotic pressure = 2.054torr* (1atm/760torr) = 2.70x10⁻³atm

c is molar concentration of the protein,

R is gas constant = 0.082atmL/molK

And T is absolute temperature = 298K

Solving the molar concentration:

c = π / RT

c = 2.70x10⁻³atm / 0.082atmL/molK*298K

c = 1.106x10⁻⁴ moles protein / L

The moles of protein in 150mL = 0.150L:

0150L * (1.106x10⁻⁴ moles protein / L) = 1.659x10⁻⁵ moles protein

The molar mass is the ratio of mass and moles:

0.231g / 1.659x10⁻⁵ moles protein =

Answer:

c. nilai pH kurang dari 7

Explanation:

cuka adalah acid

nilai pH bagi acid adalah

antara 1 hingga 6

Answer:

Newton's second law

Explanation:

It is mentioning acceleration and mass

Newton's second law's equation = F = m*a

Hope u understood

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Thank You

Answer: The equilibrium will shift in the direction of [tex]NH_3[/tex]

Explanation:

The chemical equation for the aqueous solution of ammonia follows:

[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]

According to Le-chtelier's principle:

If there is any change in the variables of the reaction, then the equilibrium will shift in that direction of equilibrium to minimize the effect.

If we add more amount of [tex]NH_4^+[/tex] to the solution, more of the products will be present. But according to Le-chtelier's principle, to minimize this effect, the equilibrium will shift in the backward direction that in the direction of [tex]NH_3[/tex]

Hence, the equilibrium will shift in the direction of [tex]NH_3[/tex]

Answer:

Throughout the below section of explanation, the two possible steps are provided.

Explanation:

Answer: C4H10

Explanation: [tex]\left \{ {{12x+y=58} \atop {\frac{12x}{58} =82,8%}} \right. \\[/tex]%

==> x=4, y=10    C4H10

QUËSTIONS :- what are the difference between ionic bond and covalent bond?

IONIC BONDS :- THEY R BONDS WHICH R FORMED DUE TO THE COMPLETE TRANSFER OF ELECTRONS BETWEEN TWO ATOMS

COVALENT BONDS :- THEY R THE BONDS WHICH R FORMED DUE TO INCOMPLETE TRANSFER OF ELECTRONS BETWEEN TWO ATOMS

IONIC BONDS R MORE STRONGER.

Explanation:

Ionic bond is much stronger than covalent bond because it involves complete transfer of electrons because of which there is formation of cation and anion and there exist huge electrostatic forces of attraction. They also have high melting and boiling point which proves that the ionic bond is very strong.

Differences between ionic bond and covalent bond :

Ionic Bonds. Covalent Bonds

Polarity :High. Low

Shape : No definite shape. Definite shape

Melting Point :High Low

Boiling Point: High Low

Answer:

[tex]304cm = 3.04m \\ 67kg = 67000g[/tex]

Explanation:

[tex]100cm \: = 1m \\ 304cm = x \\ use \: \: cross \: multipication \\ 100x = 304 \\ \frac{100x}{100} = \frac{304}{100} \\ x = 3.04m[/tex]

-------------------------------------------------

[tex]1kg = 1000g \\ 67kg = x \\ \\ use \: cross \: \: multipication \\ 1x = 67 \times 1000 \\ x = 67000g[/tex]

Hope this helps

Have a nice day!

➡ ANSWER

☑ C. 3.5 105 Hz

Answer:

See explanation

Explanation:

According to the particulate theory of matter, gas particles do not interact with each other. A gas is composed of isolated particles moving at high velocities and collide frequently with each other and the walls of the container.

Since the particles of a gas are mostly isolated, it is easy to compress the gas when pressure is applied thereby bringing the gas particles closer together.

On the other hand, in the solid state, the particles that compose matter are close together. These particles only vibrate about their mean positions due to strong intermolecular interaction between particles. The fact that the particles of the solid ion are so close together makes the solid iron lump to possess high density.

Answer:

i) ciclobutano

ii) 3-etil-4-metil ciclopenteno

Explanation:

Toda la idea de la nomenclatura IUPAC es permitir que la estructura de la sustancia se derive de su nombre y viceversa.

La nomenclatura IUPAC es un sistema universalmente aceptado para nombrar compuestos químicos.

los nombres de los compuestos enumerados son;

i) ciclobutano

ii) 3-etil-4-metil ciclopenteno

Answer:

Emulsion

Explanation:

According to Oxford dictionary, a colloid is, ''a homogeneous non-crystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.''

An emulsion is a dispersion of a liquid in a liquid. This means that the the physical state of dispersed phase and dispersion medium is same.

Examples of emulsions include; Vinaigrette, homogenized milk and hair cream.

Answer:

Sodium atoms due to being smaller in size have high ionization energy and thus, it can't lose electrons easily and is more stable and less reactive. ... Hence, from this it is clear that sodium is less reactive than potassium.

Explanation:

Answer:

Step 9

Explanation:

The reason i selected step 9, is if you take a look at the picture hes setting up a funnel,With filter paper and if you take a look at number ''9'' questions it says set up a funnel, filter paper and filter flask which is shown in the picture on top that's how i got my answer