Please help! I don't know how to do and want to understand

Answer:

STP is 101.325 kPa pressure and 273K temperature

Also, at STP, 1 mol of an ideal gas = 22.4 L

Since the question states that 22.4 L are needed at STP, we know that ONE MOLE is needed.  Now, the question is, how many moles are actually present?

V = 25.0 L

P = 101.5 kPa

T = 373K

n = ?

R = 8.31 L-kPa/Kmol

Solving the ideal gas law for n (moles) and comparing that to 1 mole, we have...

n = PV/RT = (101.5)(25.0)/(8.31)(373)

n = 0.82 moles of gas.  THIS IS NOT ENOUGH as it is less than the ONE mole required.

Explanation:

The equation is balanced.

The number of P atoms in the reactant side is 4 and the number of P atoms in the product side is also 4.

The number of O atoms in the reactant side is 16 and the number of O atoms in the product side is also 16.

The number of H atoms in the reactant side is 12 and the number of H atoms in the product side is also 12.

These results are in accordance with the law of conservation of mass.

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Answer:

The empirical formula is: CH2

Th powder is not vainillin

Explanation:

We can find empirical formula of a compound CₐHₓOₙ knowing that moles CO2 = Moles C, 2 Moles H2O = Moles H and that we can find the mass of oxygen by the difference of masses of the atoms:

Moles C = Moles CO2 -Molar mass: 44.01g/mol-

5.875g * (1mol/44.01g) = 0.1335 moles C * (12.01g/mol) = 1.60gC

Moles H2O and moles H -Molar mass: 18.01g/mol-

2.41g H2O * (1mol / 18.01g) = 0.1339 moles H2O * (2mol H / 1mol H2O) =

0.2676 moles H * (1g/mol) = 0.27g H

The empirical formula of this compound is the ratio of C:H:

0.2676 moles H / 0.1335 moles C = 2

The empirical formula is:

CH2

In vainillin, the moles of Carbon = Moles of Hydrogen. the experiment shows the moles of hydrogen are twice the moles of carbon. Thus, the powder is not vainillin

Answer:

A. Li= 5.6 g O2= 6.4 g

Explanation:

Lithium oxide, Li2O, is an oxide that contains 2 moles of Li and 1 mole of O per mole of oxide. To solve this question we must find the mass of each atom in the molecule as follows:

2Li = 2*6.941g/mol = 13.882g/mol

O = 1*16g/mol = 16g/mol

Molar mass Li2O:

16+13.882 = 29.882g/mol

The mass of lithium is:

12g * (13.882g/mol / 29.882g/mol) = 5.6g Li

And the mass of oxygen:

12g * (16g/mol / 29.882g/mol) = 6.4g O

Right answer is:

Answer: There are [tex]12.71 \times 10^{-9}[/tex] moles present in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr.

Explanation:

According to the mole concept, there are [tex]6.022 \times 10^{23}[/tex] molecules present in 1 mole of a substance.

Hence, moles in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr are calculated as follows.

[tex]Moles = \frac{2.11 \times 10^{14}}{6.022 \times 10^{23}}\\= 12.71 \times 10^{-9}[/tex]

Thus, we can conclude that there are [tex]12.71 \times 10^{-9}[/tex] moles present in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr.

Answer:

d

Explanation:

pv=nrt

2.5×1.01×10^5×8×10^-3=3×8.31×T

T=

The value of the temperature can be determined by ideal gas law and the temperature will be 0.81 K.

The average kinetic energy of particular atoms and molecules in a system is measured by the temperature.

Ideal gas law explain the relationship between pressure. temperature and volume.

Ideal gas law can be expressed as, PV=nRT.

where, P is pressure. V is volume , n is number of moles ,R is gas constant and T is temperature. It is given that, n= 3 mole, P = 2.5 atm, V = 8 L, T=?, R = 8.31.

Calculation of temperature by using ideal gas law is shown as:

Now, put the values of given data in ideal gas law equation.

T = PV/nR

=2.5×8/3×8.32

= 0.81 K

Therefore, the temperature will be 0.81K.

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Answer: hello your question has some missing details attached below is the missing details

answer : 25.5%  ( B )

Explanation:

Determine percentage yield

molar mass = 35 g/mol

mass of Li₃N(s) = 70 g

product  LiH(s) = 8.0 g ( actual yield )

theoretical yield ( LiH ) =  4 * 7.95  = 31.8 g

percentage yield = actual yield * 100 / theoretical yield

                            = 8 * 100/31.8

                            = 25.5%

Reactivity of non-metals depend on their ability to gain electrons. So, smaller is the size of a non-metal more readily it will attract electrons because then nucleus will be more closer to valence shell. ... Hence, Br is the non-metal which will be more reactive than At.

Answer:

br is more reactive than as

Considering the definition of alkanes, single bonds are found in an alkane.

Alkanes are a class of hydrocarbons (compounds containing only carbon and hydrogen) that are made up of a variable number of carbon atoms joined together by single bonds. In turn, each carbon atom bonds to hydrogen atoms, which may eventually be replaced by other atoms or functional groups.

In other words, alkanes are open or closed chain molecules that are linked by simple bonds.

Alkanes are saturated hydrocarbons because the bonds between carbon atoms are simple and stable. And as mentioned, the hydrogen atoms bonded to each carbon atom can be replaced by other atoms, such as halogens (fluorine, bromine, chlorine) or various groups or “radicals”. In the latter case, the structure becomes more complex giving rise to branched alkanes.

In summary, single bonds are found in an alkane.

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Answer: C) single only

Explanation:

just got it right

Answer:

16mL

Explanation:

Using the following formula;

CaVa = CbVb

Where;

Where

Ca = concentration/molarity of acid (M)

Va = volume of acid (mL)

Cb = concentration/molarity of base (M)

Vb = volume of base (mL)

According to the information provided in this question;

Ca (HCl) = 2M

Cb (NaOH) = 5M

Va (HCl) = 40mL

Vb (NaOH) = ?

Using CaVa = CbVb

Vb = CaVa/Cb

Vb = 2 × 40/5

Vb = 80/5

Vb = 16mL

Answer:

9

Explanation:

I took the same test :)

The stoichiometry is important in chemistry which helps us to use the balanced equation to calculate the amount of reactants and products. Here the moles of hydrogen needed is 9. The correct option is B.

The quantitative study of the reactants and products involved in a chemical reaction is known as the chemical stoichiometry. The stoichiometric coefficients can be fractions including the whole numbers.  It helps to establish the mole ratio.

The stoichiometric coefficient is basically the number which is present in front of the atoms, molecules or ions. The stoichiometric calculations are also used in gravimetry and volumetry.

Here the balanced equation for the reaction is:

N₂ + 3H₂ → 2NH₃

Number of moles of H₂ = 3 mol N₂× 3 mol H₂  / 1 mol N₂ = 9 mol H₂

So the number of moles of H₂ is 9.

Thus the correct option is B.

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Answer:

The products are already in the question Hydrogen gas and Magnesium Chloride

Explanation:

2Mg +2HCl₂ = 2MgCl₂ + H₂ balanced equation if you need it

When any metal react with acid then salt and hydrogen gas is formed. Hydrogen gas and Magnesium Chloride are formed when Magnesium is added to dilute hydrochloric acid.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

The products are Hydrogen gas and Magnesium Chloride. The balanced equation can be written as

Mg +2HCl[tex]\rightarrow[/tex] MgCl₂ + H₂

This makes bubbles of hydrogen and a colorless solution of magnesium chloride.

Therefore Hydrogen gas and Magnesium Chloride are formed when Magnesium is added to dilute hydrochloric acid.

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Answer:

B. Cation

Explanation:

As an electron is removed from the atom it is then converted into a positively charged ion known as a Cation.

Hope this helps u

Answer:

Due to increase in carbondioxide gas.

Explanation:

The buffering action of these chemical reactions is limited by the present day rate of change for atmospheric carbondioxide concentration because the the rate of atmospheric carbondioxide rises as compared to ancient atmospheric carbondioxide gas. Due to increase of human activities, the concentration of carbondioxide gas increases in the atmosphere which limits the buffering action of these chemical reactions so we can say that carbondioxide gas is responsible for its limited action.

Answer:

An lonic bond because calcium is transferring Its electrons to the chlorine.

Explanation:

Metals usually form compounds with non-metals through ionic bonding.

Metals are electropositive elements which form ions by the loss of electrons, whereas non-metals are electronegative elements which form ions by the gain of electrons.

Compounds are formed when two or more elements combine together. The formation of compounds involves formation of bonds which may be either ionic or covalent bonds.

The type of bonding that exists between the a metallic calcium atoms and non-metallic chlorine atoms in calcium chloride, CaCl₂, is ionic bonding. In the process of formation of the compound, calcium atoms which have a valency of 2 readily donates their two valence electrons to chlorine atoms to form calcium ions, Ca²+. Each chlorine atoms having a valency of 1 accepts an electron to form chloride ions Cl-. Two chlorine atoms accept the two electrons donated by a calcium ion. Due to strong electrostatic forces of attraction between the calcium ion and the two chloride ions, the ionic compound CaCl₂ is formed.

Answer:

425 and 0.28A

Explanation:

Resistance for resistors in parallel

1/ R = 1/250 +1/250

=0.008

R = 1/ 0.008 = 125

Total resistance

R= 125+ 300

=425

...

V= IR

I= V/R

I = 120/425

= 0.28 A

Answer:

The answer is c

Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Explanation:

A change that leads to the change in chemical composition of a substance is called a chemical change.

For example, [tex]2NH_{3} \rightarrow N_{2} + 3H_{2}[/tex]

Here, bond between the reactant atoms nitrogen and hydrogen is broken down.

On the other hand, bond connecting the products that is [tex]N_{2}[/tex] and [tex]H_{2}[/tex] is formed.

Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Answer:

Lead can harm production of blood cells and the absorption of calcium needed for strong bones and teeth, muscle movements, and the work of nerves and blood vessels. High lead levels can cause brain and kidney damage.

thanks

Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones where it accumulates over time. Lead stored in bone may be remobilized into the blood during pregnancy, thus exposing the fetus.

Answer:

Gold and pyrite both have a brilliant metallic luster, but are different tones of yellow. Gold is golden to silvery yellow, whereas pyrite is a pale to medium brassy yellow that sometimes tarnishes.

Explanation:

Answer:

Volume; high temperature and pressure

Explanation:

In an explosive combustion the rapid expansion of the volume causes explosion and the production of high temperature and pressure.

The substance is usually in a confined place and the expansion usually reaches a breaking point in which it is expelled from the space usually accompanied with a loud noise and high amount of temperature and pressure change thereby releasing its gas constituents.

Answer:

a. 408g de NH3 son necesarios

b. 2.42x10²³ moléculas de agua se obtienen

Explanation:

a. Basados en la reacción, 2 moles de NH3 producen una mol de (NH2)2CO. Para resolver esta pregunta debemos convertir la masa de (NH2)2CO a moles. Estas moles a moles de NH3 y su respectiva masa:

Moles (NH2)2CO -Masa molar: 60.06g/mol-

720g * (1mol / 60.06g) = 11.99 moles (NH2)2CO

Moles NH3:

11.99 moles (NH2)2CO * (2mol NH3 / 1mol (NH2)2CO) = 23.98 moles NH3

Masa NH3 -17.031g/mol-:

23.98 moles NH3 * (17.031g / mol) = 408g de NH3 son necesarios

b. 1mol de CO2 produce  1mol de agua. Se debe convertir el volumen a moles usando PV = nRT. Estas moles = Moles de agua. 1mol = 6.022x10²³ moléculas:

Asumiendo STP:

PV = nRT; PV / RT = n

Donde P = 1atm a STP

V = 9L

R = 0.082atmL/molK

T = 273.15K a STP

1atm*9L / 0.082atmL/molK*273.15K = n

n = 0.402 moles CO2 = Moles H2O

Moléculas:

0.402 moles agua * (6.022x10²³ moléculas / 1mol) =

Answer:

The answer is the first option 0.37 moles

Explanation:

the ideal gas law is PV = nRT, so in the terms of n,

n = PV/RT (divide both sides by RT to let n stand alone)

given: P = 700 kpa, V = 2L, T = 450 K , R = 8.31

n = (700 * 2) / (8.31 * 450)

= 1400/3739.5

= 0.34

Explanation:

Melting is defined as the physical process where a solid state of a substance converts into its liquid state. No change of chemical composition takes place, just the physical state of water is changing.

[tex]\text{Solid}\rightleftharpoons \text{Liquid}[/tex]

There are given carboxylic acids. The melting point of these acids increases to its second group member which is ethanoic acid due to prevalent hydrogen bonding. To break this bonding, a high amount of heat needs to be applied.

But as we move forward, the melting point decreases sharply as an increase in the number of carbon atoms decreases the hydrogen bonding.

Melting point of Formic Acid = [tex]8.3^oC[/tex]

Melting point of Acetic Acid = [tex]16.6^oC[/tex]

Melting point of Propionic Acid = [tex]-21^oC[/tex]

Answer:

Nitrogen

Explanation:

According to the Periodic Table, the atom with a mass is 16 but the Atomic number is 7 for Nitrogen. That means that Nitrogen is an isotope.

Answer: 1) 400N

2)1.6

Explanation:

1) 5cm = 100N of force

so

20cm=400n

2) 0.4 X 4 = 1.6

Answer:

Brick

Explanation:

.................

When the amount of gas in a container is increased, the volume increases. Lussac's law states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature.