How many valence electrons does it have?

pls answer thank you

Answer:

im really sorry but i dont no☹

Answer:

1. 0.0500 moles K, 0.0250 moles Cr and 0.1000 moles O.

2. 9.00 moles ammonium ions are present.

Explanation:

1. In 1mol of K2CrO4 there are 2 moles of K, 1 mole of Cr and 4 moles of O.

The moles in 0.0250 moles K2CrO4 are:

0.0250mol * 2 = 0.0500 moles K

0.0250mol * 1 = 0.0250 moles Cr

0.0250mol * 4 = 0.1000 moles O

2. In 1 mole of (NH4)2CO3 there are 2 moles of ammonium ions, NH₄⁺.

In 4,50 moles are:

4.50 moles * 2 = 9.00 moles ammonium ions are present

Answer:

B. 2.2

Explanation:

Yes, potassium metal can be used to react with an acid to prepare a soluble salt.

Acids react with metals to yield the corresponding metal salt and hydrogen gas.

One of the properties of metals is their ability to react with dilute acids to yield  a soluble salt and hydrogen gas. This is a common reaction for all metals that are above hydrogen in the activity series.

Potassium can react with a hypothetical acid HB as follows;

2K(s) + 2HB(aq) ------> 2KB(aq) + H2(g)

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Answer:

false

Explanation:

you have bromine , its a non metal and liquid in room temperature

Answer:

d.) 1.0 M HNO2, 1.0 M NaNO2

Explanation:

A buffer is a mixture that is capable of tolerating addition of a strong acid or base without altering the pH substantially.

A buffer is the mixture of a WEAK ACID AND ITS CONJUGATE BASE or a WEAK BASE AND ITS CONJUGATE ACID

In the problems:

a) HCl is a strong acid and NaCl a salt. NO buffer

b) NH3 is a weak base and NaCL a salt. NO buffer

c) HF is a weak acid and NaCl a salt. NO buffer.

Answer:

D.

Explanation:

Answer

0°C

Explanation:

substance be formed in it's solid state

Answer:

.025 ml 02

Explanation:

I made a pdf and pasted it in and etc

Answer:

1045 J

Explanation:

By using the formula Eh= mass×specific heat capacity × change in tempreture

With it being a known fact that the specific heat capacity of water is 4.16g/j/°c

Answer:

The respiratory system is the network of organs and tissues that help you breathe. basically your airways, lungs, and blood vessels so you quite literally need these to survive I mean your muscles need oxygen to function and your brain needs oxygen to function so without your respiratory system you wouldn't be able to move much and you would quickly pass out and die from the lack of oxygen to your brain there are other body processes that need oxygen as well but these are just two examples.

Explanation:

Answer:

Maybe it’s dark ??????????????

Explanation:

Hm

Answer:

E, answer 5, A positively charged atom has more protons than electrons.

Explanation:

Answer:

There are [tex]6.01\times 10^{23}[/tex] number of molecules.

Explanation:

Given that,

Volume, V = 22.4 L

Temperature, T = 0°C = 273.15 K

Pressure, P = 1 atm = 1.013 bar

We need to find the number of molecules. Let there are n number of molecules. We know that, ideal gas law is as follows :

[tex]PV=nRT\\\\n=\dfrac{PV}{RT}\\\\n=\dfrac{1.013\times 22.4}{0.08 314\times 273.15}[/tex]

n = 0.999 moles

No. of molecules,

[tex]N=n\times N_A\\\\=0.999\times 6.023\times 10^{23}\\\\N=6.01\times 10^{23}[/tex]

So, there are [tex]6.01\times 10^{23}[/tex] number of molecules.

Answer:

a) anode - hydrogen gas

cathode - oxygen gas

b) hydrogen gas - The gas burns with a pop sound

Oxygen gas - The gas rekindles a glowing splint

c) The volume of gas produced at the anode is 60cm3

Explanation:

The electrolysis of water produces two volumes of hydrogen at the anode and one volume of oxygen at the cathode.

The hydrogen gas burns with a pop sound. It is easily identified by this test. Also, oxygen is known to rekindle a glowing splint and this is a commonly used test for oxygen gas.

Since the ratio of hydrogen produced at the anode to oxygen produced at the cathode is 2:1 by volume; then when 30cm3 of oxygen is produced at the cathode, 60cm3 of hydrogen is produced at the anode.

Answer:

Electrical resistivity is a property of a material that tells you how much it resists the flow of electric current, while conductivity quantifies how easily current flows.

Answer: The molar mass of the gas is 9.878 g/mol.

Explanation:

According to Graham's law, the rate of diffusion is inversely proportional to square root of molar mass of gas.

[tex]Rate = \frac{1}{\sqrt{M}}[/tex]

where,

M = molar mass of gas

As given gas diffuses 1/7 times faster than hydrogen gas. So, its molar mass is calculated as follows.

[tex]\frac{R_{1}}{R_{2}} = \sqrt{\frac{M_{2}}{M_{1}}}\\[/tex]

where,

[tex]M_{1}[/tex] = molar mass of hydrogen gas

[tex]M_{2}[/tex] = molar mass of another given gas

[tex]R_{1}[/tex] = rate of diffusion of hydrogen

[tex]R_{2}[/tex] = rate of diffusion of another given gas = [tex]\frac{1}{7}R_{1}[/tex]

Substitute the values into above formula as follows.

[tex]\frac{R_{1}}{R_{2}} = \sqrt{\frac{M_{2}}{M_{1}}}\\\frac{R_{1}}{\frac{1}{7}R_{1}} = \sqrt{\frac{M_{2}}{2}}\\7 \times 1.414 = M_{2}\\M_{2} = 9.878 g/mol[/tex]

Thus, we can conclude that the molar mass of the gas is 9.878 g/mol.

Answer:

98.78 g/mol

Explanation:

Just took the test

Answer:

17.6kg

Explanation:

mass = Volume × Density

mass = 5000cm^3 × 3.52g/cm^3

mass = 17600g = 17.6kg

What were Lamarck's ideas about evolution and Why were those ideas incorrect?

→ These and other examples show that Lamarck's theory does not explain how life formed and became the way it is. The other way that Lamarck's theory has been proven wrong is the study of genetics. Darwin knew that traits are passed on, but he never understood how they are passed on.

Answer:

It is better to do chemistry

Explanation:

So that you will learn more of chemicals

V2 = 276 ml

Explanation:

Given:

V1 = 250 ml V2 = ?

T1 = 293K. T2 = 324K

Here, we use Charles's law:

V1/T1 = V2/T2

Solving for P2, we get

V2 = (T2/T1)V1

= (324K/293K)(250 ml)

= 276 ml

Answer:

"0.24 J/g.k" is the appropriate solution.

Explanation:

Mass of substance,

m = 110.00 g

Heat,

q = 396 J

Change in temperature,

ΔT = 15.0°C  

Now,

The specific heat will be:

⇒  [tex]q=ms \Delta T[/tex]

On putting the given values, we get

⇒  [tex]396=110.00\times s\times 15.0[/tex]

⇒  [tex]396=s\times 1650[/tex]

⇒      [tex]s=\frac{396}{1650}[/tex]

⇒         [tex]=0.24 \ J/g.k[/tex]

Carbon dioxide is released when limestone is heated during the production of [tex]\sf\purple{cement}[/tex]. ✔

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Answer:

C

Explanation:

The nucleus is very dense

Answer:

one to one

Explanation:

Answer:

In the ionic solid sodium chloride, there is one to one ratio of sodium ions to chloride ions

Answer: water

Explanation: those elements all react to water , so the answer would be water . :)

Answer:

BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB

The activity of four unknown metals based on their chemical changes is option B.

Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.

There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical changes:

1) inorganic changes

2)organic changes

3) biochemical changes

During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

Learn more about chemical change,here:

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#SPJ3

Answer:

Ca^2+

Explanation:

As we know, more energy is required to remove an electron from a positively charged ion than is required to remove an electron from a neutral atom. Hence, the second ionization energy of calcium is greater than its first ionization energy.

However, the third and fourth ionization energies of calcium are much higher than the second ionization energy because they involve removal of electrons from an inner filed shell. This process requires a lot of energy and is often not feasible.

Hence, the most common ion of calcium must be Ca^2+ where only two electrons are removed from calcium.

Explanation:

Normally, fusion involves two heavy hydrogen nuclides but since we have 4 light hydrogen nuclides, two of which underwent positron emission, thus changing two protons into neutrons plus 2 positrons and 2 neutrinos. The resulting nucleus from this fusion reaction is an He-4 nucleus.

Answer:

Explanation:

Step 1: Calculate the amount of sodium hydroxide in moles

Volume of sodium hydroxide solution = 25.0 ÷ 1,000 = 0.0250 dm3

Rearrange:

Concentration in mol/dm3 =

Amount of solutein mol = concentration in mol/dm3 × volume in dm3

Amount of sodium hydroxide = 0.100 × 0.0250

= 0.00250 mol

Step 2: Find the amount of hydrochloric acid in moles

The balanced equation is: NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

So the mole ratio NaOH:HCl is 1:1

Therefore 0.00250 mol of NaOH reacts with 0.00250 mol of HCl

Step 3: Calculate the concentration of hydrochloric acid in mol/dm3

Volume of hydrochloric acid = 20.00 ÷ 1000 = 0.0200 dm3

Concentration in mol/dm3 =

Concentration in mol/dm3 =

= 0.125 mol/dm3

Step 4: Calculate the concentration of hydrochloric acid in g/dm3

Relative formula mass of HCl = 1 + 35.5 = 36.5

Mass = relative formula mass × amount

Mass of HCl = 36.5 × 0.125

= 4.56 g

So concentration = 4.56 g/dm3