chapter 3 reactivity of metals mcq question and question and answer and important notes? ​

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Temperature change

Answer:

937.5g

Explanation:

No of moles = mass ÷ molar mass

According to this question, there are 15moles of the compound; AlCl

Molar mass of AlCl = 27 + 35.5

= 62.5g/mol

Using n = m/M.M

15 = m/62.5

m = 15 × 62.5

m = 937.5g

Answer:

C. x⁴ + 6·x³ - 12·x  - 72

Explanation:

The given functions are;

[tex]f(x) =\sqrt{x^2 + 12 \cdot x + 36}[/tex]

g(x) = x³ -12

We have that [tex]f(x) =\sqrt{x^2 + 12 \cdot x + 36}[/tex] = [tex]f(x) =\sqrt{(x + 6)^2}[/tex] =  (x + 6)

Therefore;

f(x)·g(x) = [tex]\sqrt{x^2 + 12 \cdot x + 36}[/tex] × (x³ - 12) = (x + 6) × (x³ - 12)

(x + 6) × (x³ - 12) = x⁴ - 12·x + 6·x³ - 72 = x⁴ + 6·x³ - 12·x  - 72

∴ f(x)·g(x) = [tex]\sqrt{x^2 + 12 \cdot x + 36}[/tex] × (x³ - 12) = x⁴ + 6·x³ - 12·x  - 72

Answer:

27.9 g

Explanation:

CsF + XeF₆ → CsXeF₇

First we convert 73.1 g of cesium xenon heptafluoride (CsXeF₇) into moles, using its molar mass:

As 1 mol of cesium fluoride (CsF) produces 1 mol of CsXeF₇, in order to produce 0.184 moles of CsXeF₇ we would need 0.184 moles of CsF.

Now we convert 0.184 moles of CsF to moles, using the molar mass of CsF:

9.D

10.A

11.C

12.B

13.D

14.C

15.A

16.A

18.C

Answer:

20

Explanation:

Hi there!

We need to find the atomic number of an atom that has 20 protons and 20 neutrons

the atomic number of an atom is equivalent to the amount of protons an atom has, as the number of protons determines what element an atom is.

Since the atom has 20 protons, the atomic number of the said atom is 20

Hope this helps!  

Answer:

true

false

false

true

false

true

true

false

false

true

true

Polywool fibre is synthetic.

⇒b. Synthetic

Hope It Helps You ✌️

Answer:

[tex]\large{\underbrace{\underline{\fcolorbox{White}{pink}{\bf{b.synthetic }}}}}

[/tex]

Answer:

B.Thermal insulation minimizes energy loses to the atmosphere.

Explanation:

It is important because it helps to stop hit from transferring from the calorimeter to the environment. This would help to have an accurate measurement of the heat that was used in the chemical process. The greatest cause of error that happens in calorimetry is when heat is lost to the environment. To reduce this, you insulate the calorimeter and add a cover.

Fluorine (F) and iodine(I) are the halogen elements that belong to group 17. They differ from each other as fluorine has 3 fewer energy shells than iodine. Thus, option D is correct.

Halogen is a nonmetallic element that belongs to group 17 and consists of six elements namely fluorine, bromine, tennessine, chlorine, astatine, and iodine.

They are diatomic and have 7 valence electrons in the outer shell, which makes them highly reactive and electronegative. The shielding effect is less in F than I due to the closer placement and attraction of the valence electron to the nucleus.

Fluorine differs from iodine as it has a smaller size with fewer energy shells than iodine. Iodine has five energy shells,  whereas fluorine has two energy shells that make the difference of three shells between them.

Therefore, F and I differ from each other.

Learn more about fluorine and iodine here:

https://brainly.com/question/2005537

#SPJ5

Answer:

Pb(NO₃)₂ + Na₂CrO₄ —> PbCrO₄ + 2NaNO₃

The coefficients are: 1, 1, 1, 2

Explanation:

Pb(NO₃)₂ + Na₂CrO₄ —> PbCrO₄ + NaNO₃

The above equation can be balance as follow:

Pb(NO₃)₂ + Na₂CrO₄ —> PbCrO₄ + NaNO₃

There are 2 atoms of Na on the left side and 1 atom on the right side. It can be balance by writing 2 before NaNO₃ as shown below:

Pb(NO₃)₂ + Na₂CrO₄ —> PbCrO₄ + 2NaNO₃

Now the equation is balanced.

The coefficients are: 1, 1, 1, 2

Answer:

0.535 atm

Explanation:

Since the volume of the tank is constant, we use Gay- Lussac's law to find the pressure at 180°C.

So, P₁/T₁ = P₂/T₂ where P₁ = pressure at S.T.P = 1 atm, T₁ = temperature at S.T.P = 273.15 K, P₂ = pressure of gas at 180 °C and T₂ = 180 °C = 273.15 + 180 K = 453.15 K

So, P₁/T₁ = P₂/T₂

P₂ = P₁T₂/T₁

Substituting the values of the variables into the equation, we have

P₂ = P₁T₂/T₁

P₂ = 1 atm × 453.15 K/273.15 K

P₂ = 1 atm × 1.66

P₂ = 1.66 atm

We now need to find the total number of moles of each gas present

number of moles of nitrogen = mass of nitrogen, m/molar mass of nitrogen molecule M

n = m/M

m = 2.5 g and M = 2 × atomic mass of nitrogen (since it is diatomic) = 2 × 14 g/mol = 28 g/mol

So, n = 2.5 g/28 g/mol

n = 0.089 mol

number of moles of chlorine, n' = mass of chlorine, m'/molar mass of chlorine molecule M'

n' = m'/M'

m' = 13.3 g and M = 2 × atomic mass of chlorine (since it is diatomic) = 2 × 35.5 g/mol = 71 g/mol

So, n' = 13.3 g/71 g/mol

n' = 0.187 mol

So, the total number of moles of gas present is n" = n + n' = 0.089 mol + 0.187 mol = 0.276 mol

So, the partial pressure due to nitrogen gas, P = mole fraction of nitrogen × pressure of gas at 180 °C

P = n/n" × P₂

P = 0.089 mol/0.276 mol × 1.66 atm

P = 0.322 × 1.66 atm

P = 0.535 atm

Answer:

i think is probably A

Explanation:

because at constant temperature, the product of the pressure and volume of a given mass of and ideal gass in a closed system is always constant

Answer:

I believe the answer is A or D

Explanation:

I hope this helps you out!

Answer: Dont let the water get inside your private area because it can lead to you washing out the healthy bacteria in your private area !

Explanation:

Also dont do it because you dont know if your water is clean enough for that ..

Answer:

The magnetic field of an atom, say H (one electron revolving around a proton) is composed of two separate contributions: an orbital magnetic moment and a spin magnetic moment. We get magnetic moments because of electromagnetic induction associated with each type of electron motion. The electron revolving around the proton with a certain angular momentum is related to the associated orbital magnetic moment (and, yes, we model it as a wire loop with current expressed in terms of the orbital velocity). This can be calculated using elementary mechanics. The spin magnetic moment is a little trickier because it is caused by the intrinsic spin of the electron which is a quantum phenomenon; therefore, this spin magnetic moment can only be calculated using quantum mechanics. In the end, we get a certain net magnetic moment associated with this motion of the electron in an atom. It is important to notice that this atom acts as a magnetic dipole (remember, as of yet, magnetic monopoles don't exist!).

If we take a bulk magnet like you might have on your fridge, it would be composed of atoms. Each atom operates as a magnetic dipole, but due to internal atomic structures, the atoms actually align themselves into separate magnetic domains, each with a net magnetic moment (caused my individually adding up those atomic dipole moments). In a common magnet (ferromagnet), these domains all point the same direction and stay that way, creating a permanent bulk magnetic dipole.

So in a way, there is no difference between the magnetic field of an atom and that of a magnet because one is simply a sum of the other, making both magnetic dipoles. Of course, here we see that there's nothing that fundamental about the magnetic force. In reality, the magnetic force is a relativistic effect caused by the movement of a charged particle, making electricity (i.e. charge) the underlying property at work here. Electromagnetic induction is really a shortcut to understand the magnetic force without worrying about relativistic mechanics. If we were to discover magnetic monopoles (i.e. "magnetic" charge), this would re-write a lot that we know about electromagnetism because we couldn't label all magnetic forces as by-products of moving electric charge

Answer:

There is 9.6 grams of CO2 produced

Explanation:

Step 1: Data given

Mass of methane = 5.50 grams

Molar mass of methane = 16.04 g/mol

Mass of oxygen = 13.9 grams

Molar mass of oxygen = 32.0 g/mol

Step 2: The reaction

CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)

Step 3: Calculate number of moles

Moles = mass / molar mass

Moles methane = 5.50 grams / 16.04 g/mol

Moles methane = 0.343 moles

Moles oxygen = 13.9 grams / 32.0 g/mol

Moles oxygen = 0.434 moles

For 1 mol CH4 we need 2 moles O2 to produce 1 mol CO2 and 2 moles H2O

O2 is the limiting reactant. It will completely react (0.434 moles).

There will react 0.434/2 = 0.217 moles CH4

There will remain 0.343-0.217 = 0.126 moles CH4

There will be produced 0.434 moles of H2O and

0.434/2 =0.217 moles of CO2

Step 4: Calculate mass of products

Mass = moles * molar mass

Mass CO2 = 0.217 moles ¨44.01 g/mol

Mass CO2 = 9.6 grams

Mass H2O = 0.434 moles * 18.02

Mass H2O = 7.8 grams

Answer:

NICL2 are classified as an ionic substance

Answer:

Answer below (in explanation)

Explanation:

First find the average atomic mass of the element in question (on the periodic table)

Set up the relative abundance formula: (M1)(x) + (M2)(1-x) = M(E)

Where M1 = Mass of the first isotope, X = Relative abundance, M2 = mass of the second isotope, M(E) = Atomic mass of the element

Plug in your values (i'll use nitrogen as an example) :

(background info: The mass of one isotope, nitrogen-14, is 14.003 amu and another isotope, nitrogen-15, is 15.000 amu, find the relative abundance of the isotopes.

14.003x + 15.000(1-x) =14.007

Use algebra and solve for X. First use distributive property, combine like terms, and solve for X.

It would equal X = 0.996. Multiply by 100 to get a proper percentage and the percentage abundance of Nitrogen-14 is 99.6%

This way of solving is limited to 2 isotopes only.

Done

Answer:

false, The nucleus of atoms still move around like crazy, it's just the electrons move more.

Answer:

Rust

Explanation:

it does cool chemical things

`Answer is subscribe to XoX Snead on YT Explanation: b is the answer!!

Answer:

agua

Explanation:

por que estamos en la planeta

Answer:

cfvgbhnjmk,

Explanation:

Answer:

this can helps you know the answer

Answer:

C.) The boiling point increases, and the freezing point decreases.

Explanation:

Answer:

any salt

sodium chloride

callcium chloride

potassium chloride

Explanation:

There is no general effect of temperature on the solubility of salts.effect of increase temperature on the solubilty of NaCl is not significant because it is more soluble even at low temperature. The salt like potassium iodide (KI) has negative heat of solution so it's solubility decreases with increase of temperature…

Answer:

Brownian moment means zig-Zag motion of particals Randomly anywhere in the free space or in fluids