Write the symbol for every chemical element that has atomic number greater than 55 and less than 140.8 u

Answer:

0.92g/mL

Explanation:

Density of a substance is calculated as follows:

Density = mass (m) ÷ volume (V)

According to this question, a rectangular piece of plastic has a width of 4.2 cm, a height of 1.9 cm and a length of 8.8 cm. Using the formula; L × W × H, the volume of the plastic can be calculated

V = L × W × H

V = 8.8 × 4.2 × 1.9

V = 70.2cm³

The mass of the plastic is 64.6g, hence, its density is:

Density = 64.6g ÷ 70.2cm³

Density of the rectangular plastic = 0.92g/cm³ or 0.92g/mL

Answer:

The correct answer is - C. products of nuclear fission reactions.

Explanation:

Nuclear fission is one of the nuclear reactions in which a heavy nucleus of the atom splits due to the impact of another particle or substance or it is on its own. In this reaction, there is a huge amount of kinetic energy released with more neutrons as the nucleus splits neutrons produced with energy.

The products of this reaction is newly formed atoms, kinetic energy and more neutrons and reactants is the heavy nucleus of the atom used.

Answer:

C

Explanation:

An endothermic reaction has a positive enthalpy change (∆H> 0).

An endothermic reaction is where the energy of the products is higher than that of the reactants.

∆H= energy of products -energy of reactants

Thus, ∆H is positive since the value of the energy of products is greater than that of the reactants.

Exothermic reactions have a negative ∆H.

In an endothermic reaction, heat is absorbed and thus if we were to include heat in teh chemical equation, it would be part of the reactants not products.

∆H does not indicate the amount of activation energy (Ea). All reactions have activation energy (exothermic and endothermic reactions). Activation energy is the minimum amount of energy required for the reaction to proceed.

Answer:

[tex]\boxed {\boxed {\sf C. \ The \ reaction \ is \ endothermic}}[/tex]

Explanation:

There are two main types of reactions classified according to heat: exothermic and endothermic.

The ΔH is the change in enthalpy. It is the difference between the heat of the products and the reactants (ΔH = heat of products - heat of reactants). It helps us describe a system's change in heat and classify reactions as exothermic or endothermic.

In this problem, the change in enthalpy is positive. The change in enthalpy doesn't refer to heat as a product or activation energy. Therefore, the reaction must be endothermic.

Explanation:

here's the answer to your question

Explanation:

Conjugated diene is the one that contains alternate double bonds in its structure. That means both the double bonds are separated by a single bond.

Cumulated diene is the one that contains two double bonds on a single atom. This means it has two double bonds continuously.

Isolated double-bonded compound has a single bond isolated by two to three single bonds.

Compound A: Two alkenes are joined by a sigma bond.

For example:

[tex]-CH_2=CH-CH=CH2-[/tex]

It is a conjugated diene.

Compound B: Two alkenes are joined by a C H 2 group.

It is a cumulative diene.

Compound C: Two alkenes are joined by C H 2 C H 2.

Then it is an isolated alkene.

Compound D:  A cyclohexene has a double bond between carbons 1 and 2. Carbon 3 is an sp 2 carbon that is bonded to another s p 2 carbon with an alkyl substituent.

Hence, compound D is a conjugated diene.

Answer: B- Weak base.

Explanation:

Answer:

Weak bases is your answer

Explanation:

C₅H₁₂

Isopentane/Formula

The preferred IUPɑC nɑme is the systemɑtic nɑme 2-methylbutɑne. ɑn isopentyl group is ɑ subset of the generic pentyl group. It hɑs the chemicɑl structure -CH3CH2CH(CH3)2.

Answer:

4.45 atm

Explanation:

Applying,

PV = P'V'............ Equation 1

Where P = Initial pressure of the container, V = Initial volume of the container, P' = Final pressure of the container, V' = Final volume of the container.

make P the subject of the equation

P = P'V'/V........... Equation 2

From the question,

Given: V = 55.2 L, P' = 8.53 atm, V' = 28.8 L

Substitute these values into equation 2

P = (8.53×28.8)/55.2

P = 4.45 atm

Answer:

[tex]\boxed {\boxed {\sf 4.45 \ atmospheres}}[/tex]

Explanation:

We are asked to find the pressure given a change in volume. The temperature remains constant, so we are only concerned with volume and pressure. We will use Boyle's Law, which states the volume of a gas is inversely proportional to the pressure. The formula for this law is:

[tex]P_1 V_1= P_2V_2[/tex]

The initial pressure is unknown, but the volume starts at 55.2 liters.

[tex]P_1 * 55.2 \ L = P_2V_2[/tex]

The volume is reduced to 28.8 liters and the pressure is 8.53 atmospheres.

[tex]P_1 * 55.2 \ L = 8.53 \ atm * 28.8 \ L[/tex]

We are solving for the initial pressure, so we must isolate the variable P₁. It is being multiplied by 55.2 liters. The inverse operation of multiplication is division, so we divide both sides of the equation by 55.2 L.

[tex]\frac {P_1 * 55.2 \ L }{55.2 \ L}= \frac{8.53 \ atm * 28.8 \ L}{55.2 \ L}[/tex]

[tex]P_1= \frac{8.53 \ atm * 28.8 \ L}{55.2 \ L}[/tex]

The units of liters (L) cancel.

[tex]P_1= \frac{8.53 \ atm * 28.8 }{55.2}[/tex]

[tex]P_1=\frac{245.664 }{55.2 } \ atm[/tex]

[tex]P_1 = 4.45043478261 \ atm[/tex]

The original measurements of volume and pressure have 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredths place. The 0 in the thousandths place tells us to leave the 5.

[tex]P_1 \approx 4.45 \ atm[/tex]

The initial pressure inside the container is approximately 4.45 atmospheres.

Answer:

a) 3H₂ (g) + N₂ (g) → 2NH₃ (g)

b) 2Na₂O₂ + 2H₂O → 4NaOH + O₂

General Formulas and Concepts:

Atomic Structure

Aqueous Solutions

Explanation:

a)

When we write this chemical reaction, we know that hydrogen and nitrogen are diatomic elements. Ammonia you just have to remember the chemical compound formula for. So our unbalanced equation would be:

H₂ (g) + N₂ (g) → NH₃ (g)

Now to balance this equation, we see that we have an uneven amount of hydrogens and nitrogens on both sides of the rxn. Let's balance out the nitrogens first by multiplying the products by 2:

H₂ (g) + N₂ (g) → 2NH₃ (g)

We see that now we have the number of nitrogens balanced on both sides, but our hydrogens are still unbalanced. Let's balance those by making the reactants the same number as our products:

It looks like we need to multiply 3 on the reactant hydrogens:

3H₂ (g) + N₂ (g) → 2NH₃ (g)

And we have our balanced formula!

b)

Same concept as A.

Recall how to write chemical compounds. The charge of sodium (Na) is +1 and the charge for polyatomic ion peroxide (O₂²⁻) is -2. Also recall the charge for polyatomic ion hydroxide (OH)m which is -1:

Sodium peroxide = Na₂O₂

Water = H₂O (standard knowledge)

Sodium hydroxide = NaOH

Oxygen gas = O₂

Write out our unbalanced rxn:

Na₂O₂ + H₂O → NaOH + O₂

Right away we can see that it is definitely unbalanced. We can see that we have an odd number of oxygens on both sides. We don't like odds here, so let's multiply 2 to the sodium peroxide and to make it even:

2Na₂O₂ + H₂O → NaOH + O₂

We can see that we have an even amount of oxygens on the reactant side. Now we have to balance the number of sodiums on the product side:

2Na₂O₂ + H₂O → 4NaOH + O₂

We now have the sodiums balanced. Moving onto the hydrogens. 2 on the reactant side and 4 on the product side:

2Na₂O₂ + 2H₂O → 4NaOH + O₂

We now have the hydrogens balanced. When we move on to oxygens, we can see that the number of oxygens have the same number of moles on both sides, and that would be our balanced rxn.

Answer:

Solution given:

a) hydrogen gas + nitrogen gas gives ammonia.

Balanced chemical equation:

[tex]\boxed{\bold{\green{3H_{2}+N_{2}\rightarrow 2NH_{3}}}}[/tex]

when pure and dry Nitrogen and Hydrogen gas is passed in the ratio 2:3 at 450°C temperature 200-900 ATM pressure in tye presence of iron as catalyst and molybdenum as promotor which forms Ammonia.

b) sodium peroxide + water gives sodium hydroxide + oxygen gas.

Balanced chemical equation:

[tex]\boxed{\green{\bold{3NaO_{2}+2H_{2}O \rightarrow 4NaOH +O_{2}}}}[/tex]

When sodium peroxide is combined with hot water double displacement reaction takes place and forms sodium hydroxide and oxygen gas along with heat.

Complete Question

A tank contains 100 grams of a substance dissolved in a large amount of water. The tank is filtered in such a way that water drains from the tank, leaving the substance behind in the tank. Consider the volume of the dissolved substance to be negligible. At what rate is the concentration (grams/liter) of the substance changing with respect to time in each scenario? (a) the rate after 5 hours, if the tank contains 60 L of water initially, and drains at a constant rate of 4 L/hr?

(b) the rate at the instant when 20 liters remain, if the water is draining at 2.4 L/hr at that instant g/L

c) the rate in scenario (b), if the unknown substance is also being added at a rate of 30 g/hr (and there are 100 grams in the tank at that instant)

Answer:

a)  [tex]\frac{dc}{dt}=0.10g/l/hr[/tex]

b)  [tex]\frac{dc}{dt}'=0.6g/l/hr[/tex]

c)  [tex]\frac{dc}{dt}''=2.1g/l/hr[/tex]

Explanation:

From the question we are told that:

Mass m=100g

a)

Rate [tex]t=5[/tex]

Volume [tex]V=60L[/tex]

[tex]Drain Rate =4L/hr[/tex]

Generally the equation for Concentration is mathematically given by

 [tex]c=\frac{mass}{Volume}[/tex]

Where

V=initial volume -(Drain Rate*time)

 [tex]V=60-4t[/tex]

Therefore

 [tex]c=\frac{100}{60-2.4t}[/tex]

 [tex]\frac{dc}{dt}=\frac{240}{(60-4t)^2}[/tex]

At t=5

 [tex]\frac{dc}{dt}=\frac{240}{(60-4(5))^2}[/tex]

 [tex]\frac{dc}{dt}=0.250g/l/hr[/tex]

b)

Volume [tex]v=20[/tex]

Rate [tex]\frac{dv}{dt}= 2.4[/tex]

Generally the equation for Concentration is mathematically given by

 [tex]c=\frac{100}{v}[/tex]

 [tex]\frac{dc}{dt}=\frac{-100}{V_2^2}\frac{dv}{dt}[/tex]

 [tex]\frac{dc}{dt}=\frac{-100}{20^2}*2.4[/tex]

 [tex]\frac{dc}{dt}'=0.6g/l/hr[/tex]

c)

Rate [tex]\frac{dm}{dt}[/tex]

Generally the equation for Concentration is mathematically given by

 [tex]c=\frac{m}{v}[/tex]

 [tex]\frac{dc}{dt}=\frac{30*20-(-2.4(100))}{20L}[/tex]

 [tex]\frac{dc}{dt}=\frac{30*20-(-2.4)(100)}{20}[/tex]

 [tex]\frac{dc}{dt}''=2.1g/l/hr[/tex]

Answer:

[tex][O_2]_{eq}=0.030M[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to solve this problem by firstly writing out the mathematical expression for the concentration of oxygen at equilibrium, given the initial one and the change due to the reaction extent:

[tex][O_2]_{eq}=0.050M-x[/tex]

Whereas [tex]x[/tex] can be found considering the equilibrium of SO3:

[tex][SO_3]_{eq}=2x=0.040M[/tex]

Which means:

[tex]x=\frac{0.040M}{2} =0.020M[/tex]

Thus, the equilibrium concentration of oxygen gas turns out:

[tex][O_2]_{eq}=0.050M-0.020M=0.030M[/tex]

Regards!

Answer:

Magnesium - Metallic lattice

Nitrogen - Molecules

Lithium - Metallic lattice

Potassium - Metallic lattice

Explanation:

Metals exist in metallic lattices. In this lattice, metal ions are held together with a sea of electrons by strong electrostatic forces.

All metals possess this metallic lattice, hence; potassium, lithium and magnesium all consist of metal lattices.

Nitrogen is a nonmetal and consists of molecules of N2.

Answer:

[tex]C_{10}H_8[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to find the molecular formula of the given compound by firstly calculating both moles and grams of carbon in carbon dioxide and hydrogen in water, as the only sources of these elements derived from the compound x due to its combustion:

[tex]n_C=22.35gCO_2*\frac{1molCO_2}{44.01gCO_2}*\frac{1molC}{1molCO_2}=0.51molC\\\\m_C=0.51molC*\frac{12.01gC}{1molC} =6.10gC[/tex]

[tex]n_H=3.66gH_2O*\frac{1molH_2O}{18.02gH_2O}*\frac{2molH}{1molH_2O}=0.41molH\\\\m_H=0.41molH*\frac{1.01gH}{1molH}=0.41g[/tex]

Now, since the addition of carbon and hydrogen is about 6.50 grams, we infer the compound has no oxygen, that is why we now set the mole ratios in the empirical formula for both C and H as shown below:

[tex]C:\frac{0.51mol}{0.41mol}= 1.24\\\\H:\frac{0.51mol}{0.51mol}= 1\\\\C_{1.24}H[/tex]

Yet it cannot be decimal, that is why we multiply by 4 to get the correct whole-numbered empirical formula:

[tex]C_5H_4[/tex]

Whose molar mass is 64.09 g/mol, which makes the ratio of molar masses:

[tex]\frac{128.g/mol}{64.09g/mol} =2[/tex]

Therefore, the molecular formula is twice the empirical one:

[tex]C_{10}H_8[/tex]

Regards!

Answer:

Substance A has a greater molecular mass than substance B

Explanation:

The greater the mass of a substance, the slower it will travel. If the solid formed closer to substance A, it means that substance A, travelled less and that it was slower, meaning it had a greater molecular mass.

Please mark it as brainliest if it helped you

Answer:

thank you... I would say is the answer: Subtance A has a greater molecular mass than substance B.

Explanation:

thanks for posting all the comments all the time!

have a great week... stay warm from a snow storm

Answer:

Salts will be formed and the pH of the new mixture will fall.

Explanation:

What should be: The reaction mixture should be added to the cold acid solution.

The error: Cold acid solution was added to the reaction mixture.

What happens with this?

The neutralization of a solution creates salts. The combination of positive and negative ions in the reaction also forms water. Assuming the pH of the reaction mixture was neutral before the addition of the acid, after the addition of the acid solution the pH will drop. Recall that a neutral solution has a pH of 7. So the pH of this new solution will drop to less than 7 because of the addition of an acid.

If the required procedure for the chemical process was followed, the reaction mixture added to the cold acid would have resulted in a stronger base solution. In other words, the pH of the new solution would be higher.

Answer:

0.56 M

Explanation:

Step 1: Given data

Step 2: Calculate the amount of reactant ([A]) after 28 seconds

For a first-order kinetics, we will use the following expression.

ln [A] = ln [A]₀ - k × t

ln [A] = ln 1.5 - 0.035 s⁻¹ × 28 s

[A] = 0.56 M

Answer:

Halogens

HalogensHalogens are the most reactive nonmetals on the periodic table.

Answer:

A) halogen

Explanation:

halogen are highly reactive because they are all electro negative

Answer:

1s22s22p6

Explanation:

Neon is an element in the periodic table and has an atomic number of 10, which means it has 10 protons in its nucleus and thus since the number of protons and electrons is the same then it has 10 electrons.

Therefore, it has 2 electrons in the first energy shell and 8 electrons in the second energy shell. To elaborate further, the first shell has a single s-sub shell that contains a single s-orbital that can hold two electrons. The second energy shell has a single s-sub-shell whose s-orbital will occupy 2 electrons, and also has a p-orbital which can hold 6 electrons, making the second shell to have 8 electrons.

Answer:

Following are the solution to the given points:

Explanation:

For point A:

For point B:

In point 3, the mixture was added to 100°C, which implies that the granular material flows and deforms, enabling it to become elongated. This is termed solid-state crystalline such that grains are flexible, but this material contaminates numerous little crystalline that has spheres when we cool down in point  4 polymers. It forms therefore an unstructured solid, which then in point 4 is higher in particles and less pliable in orderly atoms.

For point C:

In point 2, the specimen gets forced at room temperature to organize a huge molecule in an ordinary and crystal fashion and therefore is transparent due to highly crystalline atoms in point 2 of the PET sample.

In point 4, however, we notice how amorphous, firm but not crystalline develops. It's why light tends to disperse over many cereal limits, since many microscopic crystallines, therefore dispersion, PET in point 4 is translucent.

Answer:

There are strong intermolecular forces between particles that make up liquids, but not gases.

Explanation:

Solids, liquids and gases are the three states of matter that exists. However, they possess varying properties that distinguishes them from one another. One of these properties is the strength of the intermolecular forces that hold their molecules together.

The intermolecular forces of each state of matter becomes weak in this order: solid>liquid>gas.

- Intermolecular forces in solid molecules are very strong, hence making them compact and well attached to each other.

- Intermolecular forces in liquid molecules are not too strong, hence, cannot exist in a fixed position but tend to flow.

- Intermolecular forces in gaseous molecules are very weak, hence, gases can move easily and rapidly in any given space.

A. CH4= NON POLAR

B. CH3cl= POLAR

C. CO2= NON POLAR

D.  H2O2= POLAR

E. BCl3= NON POLAR

F. H2S​= SLIGHTLY POLAR

Answer:

A

Explanation:

More solute would typically dissolve in a saturated solution if the temperature of the solution is raised.

A saturated solution is a solution that contains the maximum amount of a particular solute the solvent can dissolve at a particular temperature.

Stirring may only increase the rate at which a solute dissolves in a solvent to make a solution but will not make more solute to dissolve in a saturated solution.

Crushing or grinding solutes into a fine powder may also increase the rate at which such solutes dissolve in a solvent to make a solution. However, it will not increase the capacity of a saturated solution to dissolve more of the solute.

Solubility is generally known to increase with an increase in temperature because the increase in the kinetic energy of the molecules of the solvent results in an increase in the efficiency with which they break apart or dissolve the solute molecules.  

The correct option is, therefore, A.

Answer:

- Two black balls: they represent a diatomic molecule composed by two atoms of the same element.

- One black ball and two black balls: they represent a compound formed by two different elements.

- One gray ball and two black balls: they represent a compound formed by two different elements.

- Two black-dotted balls: they represent a diatomic molecule composed by two atoms of the same element.

Explanation:

Hey there!

In this case, according to the given information, we can firstly bear to mind the fact that each ball color represents a different element, for that reason we can tell the following:

- Two black balls: they represent a diatomic molecule composed by two atoms of the same element.

- One black ball and two black balls: they represent a compound formed by two different elements.

- One gray ball and two black balls: they represent a compound formed by two different elements.

- Two black-dotted balls: they represent a diatomic molecule composed by two atoms of the same element.

Regards!

Answer:

you first get the unbalanced equation to show the various products and reactants. then, you write down the atoms in each element(quantity). add the coefficients so it's equal on both sides, and get state of matter

Explanation:

Answer:

the properties are:

these are all the properties but I think the two a solute needs to satisfy are

I hope this helps

Answer:

Explanation:

since HCL is a strong acid, -log(0.005) = 2.30 pH

Answer:

122

Explanation:

because after exercises heart beat increases

El hidrógeno es el elemento químico de número atómico 1, representado por el símbolo H. Con una masa atómica de 1.00784 u  ​ es el más ligero de la tabla periódica de los elementos. Por lo general, se presenta en su forma molecular, formando el gas diatómico H₂ en condiciones normales.