Please help me answers

Answer: Mendeleev's periodic law : The properties of element are a periodic function of the atomic masses . Limitations:-(1)positions of hydrogen is not correctly placed. (2) The positions of isotopes could not be explained . For ex:- cl35 are cl37 are placed in the same group.

Explanation:

hope it's helpful

Explanation:

its is classified as ionic cyrstal

Answer:Option (b) is the correct answer.

Explanation:

When a neutral element loses an electron then it acquires a positive charge and it is known as a cation.

For example, when a neutral iron atom loses three electrons then it forms a  ion.

On the other hand, when a neutral element gains an electron then it acquires a negative charge and it is known as a anion.

For example, a sulfate ion means  ion.

Thus, we can conclude that out of the given options sulfate is not a cation.

Explanation:

Mass of water vapor produced : 0.90 g

Given

0.10 g of hydrogen reacted with 0.80 g of oxygen

Required

mass of water vapor produced

Solution

Reaction

2H₂ + O ⇒ 2H₂O

If we refer to the law of conservation of mass which states that the mass before and after the reaction is the same, then the mass of water vapor formed as a product is:

mass reactants = mass products

mass of Hydrogen + mass of Oxygen = mass of water vapor

0.1 g + 0.8 g = 0.90 g

Or we can also solve by using stochiometry (using the concept of moles) to find the mass of water vapor

Answer:

6

Explanation:

The final temperature of the metal block : t=69.5 °C

Given

0.84 g water

Aluminum block = 51 g

Required

The final temperature

Solution

Enthalpy of vaporization of water is 44.0kJ/mol = 2.44 kJ/g=2440 J/g

Q out=Q in

Q releases = Q absorbed

Q water = Q Aluminum

m.Lf = m.cs.ΔT

0.84 x 2440 J/g = 51 x 0.903 J/g C x (t-25)

2049.6=46.053(t-25)

t=69.5 °C

.

Answer:

B.

Explanation:

Because one or more substances,the reactants are converted into one or more Different substances,the products. Hope this helps

Answer:

For question 15, we use cloths, heat-resistant gloves. (From what I know, I am just a 7th grader. Forgive me.)

For question 16, we use bowls to drink soup, metal cans which we use to drink soda from, we use lunch boxes which are insulated or thermos can be used for bringing to school to eat lunch and keeping food warm, we use aluminium foil containers to keep food warm.

For question 17, I think it's related to chart above question 15 and etc, if it isn't then I don't think I may be able to help.

Answer:

[tex]m_{Fe}=171.7gFe[/tex]

Explanation:

Hello!

In this case, since we have 245 of iron (III) oxide, we first need to compute the moles contained there:

[tex]n_{Fe_2O_3}=245gFe_2O_3*\frac{1molFe_2O_3}{159.7gFe_2O_3} =1.54molFe_2O_3[/tex]

Now, as 1 mole of iron (III) oxide is related to 2 moles of iron, due to iron's subscript in the molecule, we get the moles of iron itself:

[tex]n_{Fe}=1.54molFe_2O_3*\frac{2molFe}{1molFe_2O_3} =3.08molFe[/tex]

And the mass is computed based on the atomic mass of iron:

[tex]m_{Fe}=3.08molFe*\frac{55.8gFe}{1molFe} \\\\m_{Fe}=171.7gFe[/tex]

Best regards!

Explanation:

B.Electroplating involves passing an electric current through a solution called an electrolyte. A redox reaction is spontaneous if the standard electrode potential for the redox reaction is positive

Answer:

56g the time to convey he must take care of the full stops and then try to combine the two sentences that the time to convey

Answer:24

Explanation:

Answer:

wow 15 points is alot

Explanation:

Answer:

Change occur in heat energy.

Explanation:

Change occur in the heat energy of molecules during condensation process. The molecules of gas releases its heat energy and converted into liquid state. With this heat energy, they are active and escape from each other but when the heat energy is removed from them, the attractive forces between these gas molecules are formed which convert them into liquid state so change in heat energy occur in the condensation process.

Answer:

3.09 atm

Explanation:

Given that:

Volume of container A = 717 mL

Pressure of container A = 2.80 atm

Volume of container B = 174 mL

Pressure of container B = 4.30 atm

Now, if the valve are being removed and the gases are allowed to mix together; then

The total final pressure can be calculated by using the formula:

[tex]P_f = \dfrac{P_AVA+P_BV_B}{V_A+V_B}[/tex]

[tex]P_f = \dfrac{2.80*717+4.30*174}{717+174}[/tex]

[tex]P_f = \dfrac{2007.6+748.2}{891}[/tex]

[tex]P_f = \dfrac{2755.8}{891}[/tex]

[tex]\mathbf{P_f =3.09 \ atm}[/tex]

The absence of the intermolecular attraction between the atoms or molecules is called an ideal gas.  The pressure of the resultant mixture is 3.09 atm.

The relationship between the pressure and the volume of the gas is given by Boyle's law which states the inverse proportionality relation with the volume.

Given,

The volume of container A = 717 mL

The volume of container B = 174 mL

The pressure of container A = 2.80 atm

The pressure of container B = 4.30 atm

The total final pressure of the ideal gas of the mixture is calculated by:

[tex]\begin{aligned} \rm P_{f} &= \rm \dfrac{P_{A}V_{A}+ P_{B}V_{B}}{V_{A}+V_{B}}\\\\&= \dfrac{2007.6 +748.2}{891}\\\\&= 3.09 \;\rm atm\end{aligned}[/tex]

Therefore, the total pressure of the mixture is 3.09 atm.

Learn more about pressure here:

https://brainly.com/question/13534890

Answer:

16480 Kg

Explanation:

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

Volume of Hydrogen = 200000 m³

Density of Hydrogen = 0.0824 g/L

Mass of Hydrogen (in Kg) =?

Next, we shall convert 200000 m³ to L. This can be obtained as follow:

1 m³ = 1000 L

Therefore,

200000 m³ = 200000 m³ × 1000 L / 1 m³

200000 m³ = 2×10⁸ L

Thus, 200000 m³ is equivalent to 2×10⁸ L.

Next, we shall determine the mass of Hydrogen. This can be obtained as follow:

Volume of Hydrogen = 2×10⁸ L

Density of Hydrogen = 0.0824 g/L

Mass of Hydrogen =?

Density = mass /volume

0.0824 = mass of Hydrogen / 2×10⁸

Cross multiply

Mass of Hydrogen = 0.0824 × 2×10⁸

Mass of Hydrogen = 16480000 g

Finally, we shall convert 16480000 g to kg in order to obtain the desired result. This can be obtained as follow:

1000 g = 1 kg

Therefore,

16480000 g = 16480000 g × 1 kg / 1000 g

16480000 g = 16480 Kg

Thus, the mass of Hydrogen used to fill the airship was 16480 Kg

Answer:

(a) 0.135 nm; 135 pm

(b) 3.70 × 10⁶ Au atoms

Explanation:

The radius of an atom of gold (Au) is about 1.35 A. (a) Express this distance in nanometers (nm) and in picometers (pm). (b) How many gold atoms would have to be lined up to span 1.0 mm.

(a)

Step 1: Convert the radius to meters

We will use the conversion factor 1 m = 10¹⁰ A.

1.35 A × 1 m/10¹⁰ A = 1.35 × 10⁻¹⁰ m

Step 2: Convert the radius from m to nm

We will use the conversion factor 1 m = 10⁹ nm.

1.35 × 10⁻¹⁰ m × 10⁹ nm/1 m = 0.135 nm

Step 3: Convert the radius from m to pm

We will use the conversion factor 1 m = 10¹² pm.

1.35 × 10⁻¹⁰ m × 10¹² pm/1 m = 135 pm

(b)

Step 1: Convert "1.0 mm" to meters

We will use the conversion factor 1 m = 10³ mm.

1.0 mm × 1 m/10³ mm = 1.0 × 10⁻³ m

Step 2: Calculate how many gold atoms would have to be lined up to span 1.0 × 10⁻³ m

We will divide 1.0 × 10⁻³ m by 2 times the radius (diameter) of an atom of gold.

1.0 × 10⁻³ m / (2 × 1.35 × 10⁻¹⁰ m) = 3.70 × 10⁶

Answer:

5.14 * 10^24 molecules H2O

Explanation:

8.54 moles of H2O contains 8.54 x 6.022 x 10^23 = 5.14 x 10^24 molecules of H2O.

Answer:

1) Acid

2) heat

Explanation:

Dehydration is a type of chemical reaction in which water is removed from an alkanol to yield one or more alkenes.

The reaction normally commences with a protonation of the -OH group by a proton from the acid. Water is always a good leaving group so it quickly departs creating a carbocation. The removal of a proton yields the alkene.

The major product is the one in which there is greater substitution around the C=C double bond.

x = 10, y = 20/6

Given

one number is three times of the other

their arithmetic mean is 10

Required

The numbers

Solution

Suppose the numbers you are looking for are x and y, then :

x = 3y (equation 1)

The arithmetic mean : the average of values

(x+3y)/2=10

x+3y = 20 (equation 2)

Substitute equation 1 into equation 2

3y+3y=20

6y=20

y = 20/6

from equation 1 :

x= 3 x 20/6

x = 60/6

x = 10

Answer:

Mass = 46.52 g

Explanation:

Given data:

Mass of sodium phosphate react = 49.33 g

Mass of calcium phosphate produced = ?

Solution:

Chemical equation:

2Na₃PO₄ + 3Ca(NO₃)₂       →     Ca₃(PO₄)₂ + 6NaNO₃

Number of moles of Na₃PO₄:

Number of moles = mass/molar mass

Number of moles = 49.33 g/ 163.94 g/mol

Number of moles = 0.300 mol

now we will compare the moles of Na₃PO₄ and Ca₃(PO₄)₂

                Na₃PO₄         :             Ca₃(PO₄)₂

                    2                :               1

                 0.300           :             1/2×0.300 = 0.15

Mass of Ca₃(PO₄)₂:

Mass = number of moles × molar mass

Mass = 0.15 mol × 310.14 g/mol

Mass = 46.52 g

Answer:

0.9537g is the original mass of Zn in the mixture

Explanation:

We can solve this question using the molar mass of each compound involved:

Mg = 24.305g/mol

MgO = 40.304g/mol

Zn = 65.38g/mol

ZnO = 81.38g/mol

Mg-Zn:

1.0875g = 24.305X + 65.38Y (1)

Where X are moles of Mg and Y moles of Zn

MgO-ZnO:

1.4090g = 40.304X + 81.38Y (2)

(1.4090g - 81.38Y) / 40.304 = X

0.03496 - 2.0192Y = X

Replacing (2) in (1)

1.0875g = 24.305(0.03496 - 2.0192Y) + 65.38Y

1.0875 = 0.8497 - 49.077Y + 65.38Y

0.2378 = 16.303Y

0.01459 moles of Zn = Y

And the mass is:

0.01459 moles of Zn * (65.38g/mol) =

Answer: 20.775 g S

Explanation: 3.9x10^23 atoms = 0.648 mol

Atomic mass S = 32.08

S in grams = 20.775

Answer:

the property that is shared between liquids us called thermometric property your welcome

Answer:

0.13M and 0.16m.

Explanation:

Molarity is defined as the moles of solute present in 1L of solution.

Molality is the moles of solute per kg of solvent.

To solve this problem we need to convert the mass of sucrose to moles using its molar mass and finding the volume in L of the solution and the mass in kg of solvent:

Moles sucrose:

Molar mass:

12C = 12*12.01g/mol = 144.12g/mol

22H = 22*1.005g/mol = 22.11g/mol

11O = 11*16g/mol = 176g/mol

Molar mass of sucrose is 144.12g/mol + 22.11g/mol + 176g/mol = 342.23g/mol

Moles are:

19.0g * (1mol / 342.23g/mol) = 0.0555 moles of sucrose

Liters solution:

425mL * (1L / 1000mL) = 0.425L

kg solvent:

425mL * (0.82g/mol) = 348.5g * (1kg / 1000g) = 0.3485kg

Molarity:

0.0555 moles / 0.425L

Molality:

0.0555 moles / 0.3485kg

Answer:

A. A solid mixture is heated. One component transitions directly between solid and gas ---> Sublimation

B. A liquid is carefully poured out, leaving the solid behind in the container ----> Decantation

C. A solvent is added to dissolve only one mixture component and then the liquids are separated ----> solvent extraction

D. A solid is caught on paper or a membrane while the liquid passes through ---> Filtration using filter paper

Explanation:

A. Sublimation is a process of separating solids which sublimes (solids turning directly to gases) from a a mixture of other solids which do not sublime. When the mixture is heated, the solids which sublime are separated and those which do not are left behind. examples of solids which sublime are naphthalene, Iodine crystals, etc.

B. Decantation is the process of carefully pouring out a liquid from a mixture of it with a solid, leaving the solid behind. Example, a mixture of sand and water where water can be easily decanted, leaving the sand behind.

C. In the process of solvent extraction, a mixture of solids which are soluble in different solvent, one of the components is dissolved in a solvent in which it is soluble while the others are not. The solution is then filtered out and the solid is then separated from the solvent by evaporation.

D. In filtration using a filter paper, the solid-liquid mixture is passed through a filter paper which has pores the size through which liquids can pass through but the solid can not. therefore, the solid remains behind on the paper while the liquid passes through.

A is sublimation, B is decantation, C is solvent extraction, and D is filtration.

Chemical mixtures are separated in different ways.

More on separation of mixtures can be found here: https://brainly.com/question/863988

Answer:

In order to create a Bohr model for carbon, you must start in the first shell of electrons. The first shell can hold up to 2 of carbons 6 electrons. After filling up the first shell you can move on to the second that can hold up to 8 electrons. The finished Bohr model would have 2 electrons in the first shell and 4 in the second shell.

Explanation:

Answer:

elemnt b

Explanation:

Answer:

[tex]m_{Li_3N}=9.06gLi_3N[/tex]

Explanation:

Hello!

In this case, since the reaction between nitrogen and lithium to obtain lithium nitride is:

[tex]6Li+N_2\rightarrow 2Li_3N[/tex]

Starting by that amount of atoms of lithium, we first need to compute the moles of lithium via the Avogadro's number:

[tex]n_{Li}=4.7x10^{23}atoms*\frac{1molLi}{6.022x10^{23}atoms}=0.78molLi[/tex]

Now, by using the 6:2 mole ratio between lithium and lithium nitride and the molar mass of this product (34.83 g/mol), we can compute the required grams as shown below:

[tex]m_{Li_3N}=0.78molLi*\frac{2molLi_3N}{6molLi}*\frac{34.83gLi_3N}{1molLi_3N} \\\\m_{Li_3N}=9.06gLi_3N[/tex]

Best regards!