Plz help me I am!!!!

Answer:

The sample of __Ca___ contains the greatest number of atoms

Explanation:

As we know,

1 mole [tex]= 6.022*10^{23}[/tex] molecular entities (Can be atom, ions or molecules)

Number of atoms in 1.76 mole sample of Be

[tex]= 6.022*10^{23} *1.76\\= 1.059 * 10^{24}[/tex]

The sample of __Ca___ contains the greatest number of atoms

Answer:

A.

Explanation:

In an endothermic reaction heat is applied.

In an endothermic process, heat is transferred from the surroundings to the system.

What are endothermic and exothermic processes?

An exothermic process is one that gives off heat. This heat is transferred to the surroundings. An endothermic process is one in which heat has to be supplied to the system from the surroundings.

The endothermic process is a term that describes a reaction where the system absorbs the energy from its surrounding in the form of heat. A few examples of the endothermic process are photosynthesis, evaporating liquids, melting ice, etc.

The exothermic reaction is the opposite of an endothermic reaction. It releases energy by light or heat to its surrounding. A few examples are neutralization, burning of a substance, reactions of fuels, etc.

Hence, option A is the correct answer.

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Answer: 1. Highest osmotic pressure : 1 M [tex]MgCl_2[/tex]

2. Lowest osmotic pressure:  1 M [tex]C_{12}H_{22}O_{11}[/tex]

Explanation:

[tex]\pi=i\times C\times R\times T[/tex]

[tex]\pi[/tex]= osmotic pressure

i = Van'T Hoff factor  

C = concentration  

T = Temperature  

1. For 1M [tex]MgCl_2[/tex]  

, i= 3 as it is a electrolyte and dissociate to give 3 ions.

[tex]MgCl_2\rightarrow Mg^{2+}+2Cl^{-}[/tex]  

2. For 1 M [tex]KCl[/tex]

, i= 2 as it is a electrolyte and dissociate to give 2 ions.

[tex]KCl\rightarrow K^{+}+Cl^{-}[/tex]

3. For  1M [tex]C_{12}H_{22}O_{11}[/tex]

, i= 1 as it is a non electrolyte and do not dissociate.  

Thus as vant hoff factor is highest for [tex]MgCl_2[/tex] thus osmotic pressure is highest for 1 M [tex]MgCl_2[/tex]

And as vant hoff factor is lowest for [tex]C_{12}H_{22}O_{11}[/tex] thus osmotic pressure is lowest for  1 M [tex]C_{12}H_{22}O_{11}[/tex]

Answer:

The Lewis structure for the sulfate ion consists of a central sulfur atom with four single bonds to oxygen atoms. This yields the expected total of 32 electrons. Since the sulfur atom started with six valence electrons, two of the S-O bonds are coordinate covalent.

Explanation:

Then that means it has both.

Shaking causes small bubbles, which helps the soda's carbon dioxide escape faster. The gas will gradually escape from the liquid as bubbles once the can is opened, and the soda will become "flat." The dissolved gas takes a long time to escape if the liquid is treated gently.

Answer:

C.

Explanation:

The statement which is  given below describe a homogeneous catalyst.

"It is in the same phase as the reactants"

The catalyst which have similar phase to the reactant of the reaction is called homogeneous catalyst.

Mostly in  homogeneous catalyst, catalyst present in liquid form.

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Answer:

Convergent Plate Boundaries

Explanation:

I hope this helps :)

Answer:

The limiting reactant is: H₂O

265.3 g of K₂Sn(OH)₆ are formed in the reaction.

Explanation:

The reaction is:

Sn(s) + 2KOH (aq) + 4H₂O(l)  → K₂Sn(OH)₆ (s) + 2H₂ (g)

The first step to solve is to determine the moles of each reactant:

We controlled that reaction is ballanced.

122 g . 1mol / 118.71g = 1.03 moles of Sn

134g . 1mol /56.1g = 2.39 moles of KOH

63.9 g .1mol /18g = 3.55 mol of water

Stoichiometry is 1:2:4.

Sn is the lowest reactant and water, the highest, but I can see, that water is the limiting.

1 mol of Sn needs 4 moles of H₂O to react

Then, 1.03 moles of Sn may react to (1.03 . 4)/1 = 4.12 moles.

We only have 3.55 moles. It's ok.

2 moles of KOH need 4 moles of H₂O to react

Then, 2.39 moles of KOH may react to (2.39 . 4) /2 = 4.78 moles.

We only have 3.55, there's no enough water.

So 4 moles of water can produce 1 mol of potassium hydroxystannate

Then, 3.55 moles of H₂O may produce (3.55 . 1)/4 = 0.8875 moles.

We convert moles to mass: 0.08875 mol . 298.91g /1mol =265.3g

Answer:

100 g/mol

Explanation:

The equation of the reaction;

Ca^2+(aq) + EDTA(aq) -----> (CaEDTA)^2-(aq)

Let CA = concentration of EDTA

VA = volume of EDTA

NA= number of moles of EDTA

CB= concentration of marble

VB = volume of marble

NB= number of moles of marble

CAVA/CBVB = NA/NB

CAVANB=CBVBNA

CB = CAVANB/VBNA

CB = 0.01052 *  23.56  * 1/10.00  * 1

CB = 0.02479 M

number of moles = concentration * volume

number of moles = 0.02479 M * 100.00/1000L

number of moles = 2.479 * 10^-3 moles

number of moles = mass/molar mass

molar mass =  0.2481g/2.479 * 10^-3 moles

molar mass =  100 g/mol

Answer:

69mol

Explanation:

The balanced chemical equation given in this question is as follows;

N₂ + 3H₂ → 2NH₃

The above balanced equation shows that 3 moles of hydrogen gas (H2) reacts to produce 2 moles of ammonia (NH3).

To convert the given mass of hydrogen to moles, we use the following formula:

mole = mass/molar mass

Molar mass of H2 = 2g/mol

mole = 207/2

= 103.5mol

If 3 moles of H2 produce 2 moles of NH3,

Then, 103.5mol of H2 will produce 103.5 × 2 / 3

= 207/3

= 69mol

Answer:

Calcium flouride?

Explanation:

Quite self explanatory

Answer: 1672 Joules

Explanation:

The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

[tex]Q=m\times c\times \Delta T[/tex]

Q = Heat absorbed by water = ?  

c = heat capacity of water = [tex]4.18 J/g^0C[/tex]

Initial temperature of the water = [tex]T_i[/tex] = [tex]27^0C[/tex]

Final temperature of the water  = [tex]T_f[/tex]  = [tex]35^0C[/tex]

Change in temperature ,[tex]\Delta T=T_f-T_i=(35.0-27.0)^0C=8.0^0C[/tex]

Putting in the values, we get:

[tex]Q=50.0g\times 4.18J/g^0C\times 8.0^0C=1672J[/tex]

As heat absorbed by water is equal to the heat released by metal, the Joules of heat transferred are 1672 Joules

Answer:

894 deg K

Explanation:

The computation is shown below:

Given that

V1 denotes the initial volume of gas = 2.00 L  

T1 denotes the initial temperature of gas = 25 + 273 = 298 K  

V2 denotes the final volume of gas  = 6.00 L  

T2 = ?

Based on the above information

Here we assume that the pressure is remain constant,

So,  

V1 ÷ T1 = V2 ÷ T2  

T2 = T1 × V2 ÷ V1

= (298)(6) ÷ (2)

= 894 deg K

Answer:

false

Explanation:

All the members of one species in a particular area are referred to as a population. All the different populations that live together in an area make up a community. The community of organisms that live in a particular area, along with their nonliving surroundings, make up an ecosystem.

The correct answer is solution B!

Answer:

Attached picture.

Explanation:

(1) Ksp equals the product of [Co 2+][CO3 2-]. CoCO3 is excluded from the equilibrium expression because it is a pure solid. The mole ratio of Co 2+ and CO3 2- is 1:1 so their molar solubilities are the same.

(2) There is an initial concentration of 0.10 M Co 2+ so write that in the "I" row for Co 2+ on the ICE table. When you find the zeros of the quadratic when solving for "s", take the positive value rather than the negative value because concentration cannot be negative.

(3) Extra products will cause the equilibrium to consume products and form reactants. So the reverse reaction will occur faster than the forward reaction. More products mean an increased Q value compared to K, since the numerator of [tex]K = \frac{[products]}{[reactants]}[/tex] increases.

Answer:

0 587 mL

Explanation:

First we convert 180 grams of HCl into moles, using its molar mass:

Now we can use the number of moles and the given concentration to calculate the required volume, applying the definition of molarity:

Finally we convert liters into milliliters:

The closest answer is option C, 587 mL.

The volume needed to make an 8.40 M solution of HCl is 0.587 ml.

The correct option is C.

HCl is a strong acid. It is present in our stomach to help in digesting food.

Step1: covert 180 grams into moles

Molar mass of HCl is 36.46 g

[tex]\dfrac{180 g}{36.46 g/mol } = 4.94\; mol\; HCl[/tex]

Step2: calculate the molarity

[tex]\rm Molality = \dfrac{mol}{L}\\\\\rm L = \dfrac{4.94 mol }{8.40 M} = 0.588 L\\[/tex]

Covert the liters into ml

[tex]\dfrac{0.588 L}{1000} = 588 mL[/tex]

Thus, the volume of the solution is 588 ml., nearest is option C, 587 ml.

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Answer:

Given : Diatomic molecule at 273K

'q' absorbed = positive = +100Cal = 100 x 4.184J = 418.4J

'W' done by system = negative = -209J

By first law of thermodynamics;

ΔU = q + W = 418.4 + (-209) = 209.4J

We know for diatomic molecule Cv=25R and CvΔT=ΔU

CvΔT=209.4

 25RΔT=209.4

ΔT=5R209.4×2

And, Heat exchange=Cm×ΔT 

where; Cm is molar heat capacity

Cm=ΔTHeat Exchange

substituting values for Heat Exchange = 418.4 and ΔT=5R209.4×2

Cm=5R

Answer:

2.41x10²¹ atoms

Explanation:

mass of nickel that are present in the coin can be determined Using ( 25% nickel) with j mass of coin= 0.942g )

mass of nickel = (0.942g) × (25/100)

= 0.2355g of Nickel

We need to convert this " gram" into " moles"

Mole= mass/ molar mass

Molar mass= 58.69 g/mol

0.2355 g) / (58.69 g/mol)

= 0.004 mol

We need to convert the moles to

number of atoms.

Avogadro's number= 6.023x10²³ atoms/mol

(0.004 × 6.023x10²³ atoms/mol)

=2.41x10²¹ atoms

Answer:

about 5 hours

Explanation:

When doing this problem you mmust mulitiply 4 x 74 and divide the answer by 60 because 60=1 hour.

Answer:

[tex]\boxed {\boxed {\sf \frac {1}{3} \ mol \ Al_2O_3 \approx 0.34 \ mol \ Al_2O_3}}[/tex]

Explanation:

We will use stoichiometry to solve this problem. The reaction given has a formula of

[tex]4Al+3O_2 \rightarrow 2Al_2O_3[/tex]

The coefficients tell us the number of moles necessary for the reaction.

The reaction requires 3 moles of oxygen to produce 2 moles of aluminum oxide. We can make a ratio.

[tex]\frac {3 \ mol \ O_2}{ 2\ mol \ Al_2O_3}}[/tex]

Since we are doing the reaction with 0.5 moles of oxygen, we multiply the ratio by that number.

[tex]0.5 \ mol \ O_2 *\frac {3 \ mol \ O_2}{ 2 \ mol \ Al_2O_3}}[/tex]

Flip the ratio so the moles of oxygen cancel each other out.

[tex]0.5 \ mol \ O_2 *\frac {2 \ mol \ Al_2O_3}{ 3 \ mol \ O_2}}[/tex]

[tex]0.5 *\frac {2 \ mol \ Al_2O_3}{ 3 }[/tex]

[tex]\frac {1 \ mol \ Al_2O_3}{ 3 }[/tex]

[tex]\frac {1}{3} \ mol \ Al_2O_3 = 0.33333 \ mol \ Al_2O_3 \approx 0.34 \ mol \ Al_2O_3[/tex]

0.5 moles of oxygen produces 1/3 or approximately 0.34 moles of aluminum oxide.

Answer:

Permafrost is any part of the ground that remains completely frozen or colder

Answer:

Average atomic mass = 32.057 u

Explanation:

Average atomic mass = Σ(isotope × abundance)

Average atomic mass = (0.95 × 31.972) + (0.0076 × 32.971) + (0.0422 × 33.967)

Average atomic mass = 32.057 u