Which answer is it for number 7

Answer:

D

Explanation:

Metallic character decreases as you move across a period in the periodic table from left to right. This occurs as atoms more readily accept electrons to fill a valence shell than lose them to remove the unfilled shell. Metallic character increases as you move down an element group in the periodic table. This is because electrons become easier to lose as the atomic radius increases, where there is less attraction between the nucleus and the valence electrons because of the increased distance between them.

Answer:

High temperature and low pressure

Explanation:

According to the kinetic molecular theory, gases are composed of small particles called molecules which are in constant motion.

At high temperature and low pressure, gas molecules possess high kinetic energy and move at high velocities hence intermolecular interaction is almost none existent and real gases approach the behavior of ideal gases.

Answer:

12113

Explanation:

step by step:no

Answer:

linear

Explanation:

Actually I consulted various sources too and that was the most sought answer,I just decided to answer you before studying it too

Answer:

17

Explanation:

i need points

Answer:

Explanation:

C is oxidised because C up to C+4

PbO is reduced because PbO from Pb2+ down to Pb0

Answer:

lead (Pb) is reduced carbon is oxidized

Answer:

the volume of the acid is 250 mL.

Explanation:

Given;

number of moles of the Hcl acid, n = 0.5 mol

concentration of the acid, C = 2.0 M = 2 mol/L

let the volume of the acid = V

The volume of the acid is calculated by applying the following equation;

n = CV

V = n/C

[tex]V= \frac{0.5 \ mol}{2 \ mol/L}[/tex]

V = 0.25 L

V = 250 mL

Therefore, the volume of the acid is 250 mL.

Answer:

It is B

Explanation:

I was able to find my school notes and double-check. I hope you have a nice day!

Answer:

Explanation:

First of all, 1 mol of Sodium Sulphide has molecular mass of

S = 32

Na2 = 2*23 = 46

The formula of NaS is actually Na2S. It's molecular mass = 78

How many grams of Na2S are present

Grams present = 240 - 162 = 78 which is exactly 1 mol.

The remainder is water.

The molecular mass of water = 2 + 16 = 18

162 grams of water = 162/18 = 9 mols of water.

So the correct formula is Na2S*9H20

Answer:

Explanation:

mg +2hcl=mgcl2 +h2

mhcl=10.95g

nhcl==0.3

nmg=1/2nhcl=0.15

mMg=3.6g

m mgcl2=14.25

Answer:

TRUE

Explanation:

The blood alcohol content is also known as the blood alcohol level or the blood alcohol concentration. It is defined as the measurement of the alcohol intoxication in the body and is used for the legal or the medical purposes.

When the BAC increases in the person's body, the person started to loose clear vision, loss of short term memory, poor muscle coordination,  impaired perception and face difficulty in concentrating. Thus it becomes very difficult for a person to drive a car or ride a bike whose BAC has increased.

The driver cannot properly judge the distances between the vehicle and the speed of the vehicle.

Hence the answer is TRUE.

Answer:

2.775 g

Explanation:

Given that;

Number of moles = concentration × volume

Concentration = 0.10M

Volume =250 mL

Number of moles = 250/1000 × 0.10

Number of moles = 0.025 moles

Also;

Number of moles = mass/molar mass

Molar mass of CaCl2= 111 g/mol

Mass = Number of moles × molar mass

Mass = 0.025 moles × 111 g/mol

Mass= 2.775 g

Answer: Crystal habit and cleavage.

Explanation:

When two physical properties of minerals both bring about smooth, flat surfaces that has specific angles between them.such that the first property is externally visible and is the result of how the mineral forms while the second property is internal and is the result of breaking a sample of the mineral, it should be noted that the properties are refered to as the crystal habit and cleavage.

It should be noted that the cleavage refers to the tendency of crystalline materials to be able to split along the structural planes.

Answer: B. The Pauli exclusion principle.

Explanation: Founders Educere answer ;)

40

Explanation:

because its Saturated

Answer:

E° = -1.66 V

Explanation:

The standard reduction potential is also known as the standard electrode potentials and it tries to find the probability that an element will be reduced or undergo reduction.

From activation series online showing the standard reduction potentials for half cells, the standard reduction potential of Al3+ (aq) + 3e- -> Al(s) is;

E° = -1.66 V

Answer:

I put the right structures in the pictures for you

Answer:

1040

Explanation:

you can use the mole to mole ratios of aluminum chloride and hydrogen gas,you first have to find the number of moles of hydrogen gas..the number of moles of hydrogen gas are 11.7(23.4/2)

2AlCl3+3H2

2 : 3

x :11.7

3x/3=23.4/3

x=7.8g/mol

then find the number of grams of aluminum chloride

m=n×mr

=7.8×133.341

=1040g

I hope this helps and sorry if it's wrong

Freezing point depression is when a substance must be colder than normal in order to freeze.

Freezing point depression often occurs when a solute is added to a solvent. This reduces its freezing point. Since temperature is reduced, in other words, this means that the substance must become colder than normal for it to start freezing.

Hence, freezing point depression is when a substance must be colder than normal in order to freeze.

Learn more at: https://brainly.com/question/2785367

D. When a substance must be colder than normal in order to freeze.

Explanation:

hey love, I just took the quiz on this for founder's education. I hope this helped.

Explanation:

Aight, I'mma give tell ya an easy way for this question. look at this Forumla

M=

[tex] \frac{10ad}{m} [/tex]

a explains the percentage of aqueous solution

d is the density

m is the molar mass

right, let's just hop to it

M=10×28×1.25/11.5====> M=30.43

Answer:

The volume of [tex]\rm O_2[/tex] required would be [tex]120\; \rm cm^{3}[/tex], assuming that both the pentane and the [tex]\rm O_2\![/tex] in this question are ideal gases and are under the same temperature and pressure.

Explanation:

Balance the equation for the reaction:

[tex]\rm ?\; C_{5}H_{12} + ?\; O_2 \to ?\; CO_{2} + ?\; H_{2}O[/tex].

Start by setting the coefficient of the molecule with the largest number of atoms to [tex]1[/tex].

In the combustion of alkanes (including pentane,) consider setting the coefficient of the alkane to [tex]1\![/tex].

[tex]\rm 1\; C_{5}H_{12} + ?\; O_2 \to ?\; CO_{2} + ?\; H_{2}O[/tex].

Number of carbon atoms among the reactants: [tex]5[/tex].

Number of hydrogen atoms among the products: [tex]12[/tex].

By the conservation of atoms, there would need to be the same number of carbon and hydrogen atoms (along with the oxygen atoms) among the products.

Hence, the coefficient of [tex]\rm CO_2[/tex] would be [tex]5[/tex] while the coefficient of [tex]\rm H_2O[/tex] would be [tex]12 / 2 = 6[/tex].

[tex]\rm 1\; C_{5}H_{12} + ?\; O_2 \to 5\; CO_{2} + 6\; H_{2}O[/tex].

There would be [tex]5 \times 2 + 6 \times 1 = 16[/tex] oxygen atoms among the products. Also by the conservation of atoms, there would be the same number of oxygen atoms among the reactants.

Hence, the coefficient of [tex]\rm O_2[/tex] would be [tex]16 / 2 = 8[/tex].

[tex]\rm 1\; C_{5}H_{12} + 8\; O_2 \to 5\; CO_{2} + 6\; H_{2}O[/tex].

The ratio between the coefficient of [tex]\rm O_2[/tex] and [tex]\rm C_{5}H_{12}[/tex] in the balanced equation is:

[tex]\displaystyle \frac{n({\rm O_2})}{n({\rm C_{5}H_{12}})} = \frac{8}{1} = 8[/tex].

In other words, it would take eight [tex]\rm O_2[/tex] molecules to react with one [tex]\rm C_{5}H_{12}[/tex] molecule.

Assume that both [tex]\rm O_2[/tex] and [tex]\rm C_{5}H_{12}[/tex] are ideal gases. Under the same temperature and pressure, the volume of the two gases would be proportional to the number of molecules in each gas:

[tex]\displaystyle \frac{V({\rm O_2})}{V({\rm C_{5}H_{12}})} = \frac{n({\rm O_2})}{n({\rm C_{5}H_{12}})} = \frac{8}{1} = 8[/tex].

In other words, it would take [tex]8\; \rm cm^{3}[/tex] of [tex]\rm O_2[/tex] to react with [tex]1\; \rm cm^{3}[/tex] of [tex]\rm C_{5}H_{12}[/tex] under these assumptions. It would then take [tex]8 \times 15\; \rm cm^{3} = 120\; \rm cm^{3}[/tex] of [tex]\rm O_2\![/tex] to react with [tex]15\; \rm cm^{3}\![/tex] of [tex]\rm C_{5}H_{12}\![/tex].

Exothermic reaction is where there is release of energy during a reaction

The enthalpy of exothermic reaction is negative

The relation between energy of products, reactants and enthalpy of reaction is

Enthalpy of reaction =  sum of enthalpy of formation of products - sum of enthalpy of formation of reactants .

As enthalpy of reaction is negative, it means the enthalpy of products is less than the enthalpy of reactants  so answer is :

In an exothermic reaction the energy of the product is less than the energy of the reactants.

C.

An endothermic reaction is a reaction that absorbs heat from the surroundings. That means that the energy of the system must increase. Therefore, the answer must be C as the products should have higher energy than the reactants.

Answer:

6.23 KOH 90% son necesarios

Explanation:

Una solución 1N de KOH requiere 1equivalente (En KOH, 1eq = 1mol) por cada litro de solución.

Para responder esta pregunta se requiere hallar los equivalentes = Moles de KOH para preparar 100mL = 0.100L de una solución 1N. Haciendo uso de la masa molar de KOH y del porcentaje de pureza del KOH se pueden calcular los gramos requeridos para preparar la solución así:

Equivalentes KOH:

0.100L * (1eq / L) = 0.100eq = 0.100moles

Gramos KOH -Masa molar: 56.1056g/mol-:

0.100moles * (56.1056g/mol) = 5.61 KOH se requieren

KOH 90%:

5.61g KOH * (100g KOH 90% / 90g KOH) =

Explanation:

Solubility is defined as a property of solutes by virtue of which they get dissolved in a favorable solvent. The solute can only be dissolved in any suitable solvent up to a limit at a given temperature. This is a characteristic of the the solute-solvent pairing.

Answer:

a measuring cylinder containing water only.

Explanation:

If we want to measure the volume of an irregular object. We need a properly calibrated measuring cylinder filled with water of known volume.

The irregular object is now inserted into the measuring cylinder containing water and the change in the volume of water is noted. The volume of the irregular object is now obtained as;

New volume of water - initial volume of water.

Hence, only a measuring cylinder filled with water is required to measure the volume of a small irregularly- shaped stone.

Answer:

They will be considered ions of the same element.

Explanation:

Ions form from elements when they gain or loss an electron, causing the number of protons (positively charged) to be unequal to the number of electrons (negatively charged), resulting in a net charge.

If there are more electrons than protons (from an element gaining 1 or more electrons), the ion is negatively charged and is called an anion.

If there are more protons than electrons (via the loss of electrons), the ion is positively charged and is called a cation.

Answer:

The first one

Explanation:

9070 mm = 90.7 m

9070mm is actually equal to 9.07m

Answer:

Nobles Gases Are the group of elements which are generally unreactive

Answer:

.

Explanation: