Aluminum is a lightweight metal (density 2.70 g/cm3) used in aircraft construction, high-voltage transmission lines, and foils. what is its density in kg/m3?

The correct answer is option A. The mass of the sample decreased, so physical changes occurred as the metal first melted and then boiled out of the crucible. The decrease in mass is a result of the metal melting and then vaporizing as it is heated.

Physical changes refer to changes in the physical properties of a substance without altering its chemical composition. Examples of physical changes include melting, freezing, condensation, vaporization, sublimation, and physical state changes. Physical changes occur when a substance changes from one state of matter to another without a chemical reaction taking place.

This is an example of a physical change, as the material is changed from a solid to a liquid and then to a gas, but its chemical composition remains the same.

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518.5 atm pressure of hydrogen is needed to maintain a \(H_2\) concentration of 0.42 m

The given Henry's law constant for \(H_2\) is 8.1 × 10^-4 M atm^-1 at 25°C. To find the pressure of hydrogen needed to maintain a \(H_2\) concentration of 0.42 M, we can use Henry's law.

The equation for Henry's law is:

C = kH*P

where C is the concentration of gas in moles per liter, P is the partial pressure of the gas in atmospheres, and kH is Henry's law constant in M/atm.

Plugging the values in Henry's law equation, we get:

0.42 = (8.1 × 10^-4)P

Dividing both sides by (8.1 × 10^-4), we get:

P = (0.42)/(8.1 × 10^-4)

P = 518.5 atm

Hence, the pressure of hydrogen needed to maintain a \(H_2\) concentration of 0.42 M is 518.5 atm.

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Answer:

IM just too pogchamp

Explanation:

The condition where only four chromosomes are present in some cells of a fruit fly is known as haploidy.

Haploidy can occur due to a variety of reasons, including errors during cell division, such as nondisjunction, which is the failure of chromosomes to separate properly during meiosis. In nondisjunction, the chromosomes fail to divide equally, resulting in daughter cells with abnormal numbers of chromosomes. In the case of the fruit fly, this can result in cells with only four chromosomes instead of the normal eight.

Haploidy can also occur naturally in certain stages of development, such as during gamete formation, where cells undergo meiosis to produce haploid gametes with half the number of chromosomes as the parent cell.

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Answer: The heat capacity of a bomb calorimeter is 500 J°C.

Answer:

C, Mixture

Explanation:

Answer:

the correct answer is actually D pure substance

Explanation:

Answer:

mother

Explanation:

Answer:

Los modelos deben basarse en principios científicos sólidos.

Explanation:

Espero que esto ayude!

Explanation:

you need to review these formulas

Answer:

n = 0.19 mol

Explanation:

Given mass = 15 g

The molar mass of AsH₃ = 77.94 g/mol

We need to find the number of moles in 15 g of AsH₃. We know that,

No. of moles = given mass/molar mass

\(n=\dfrac{15}{77.94 }\\\\n=0.19\ mol\)

So, there are 0.19 g/mol. Hence, the correct option is equal to 0.19 mol.

This element is called Neon and it is part of the group known as Noble gases or group 8 and it is in period 2

Explanation:

1 metal they are likely to lose an electron

2non metals

3 Nobel gases because they are not reactive with stable valance number

TNT (Trinitrotoluene) has relatively small energy per pound, but it is a very effective explosive due to the following reasons:

1. It is an insensitive explosive: TNT has a high ignition temperature, making it less prone to accidental detonation. TNT can also resist shock and friction, making it a stable explosive.

2. High detonation velocity: TNT is capable of detonating at a speed of 6,900 m/s. This high velocity allows TNT to produce a supersonic shockwave that can cause significant damage to its surroundings.

3. High gas yield: When TNT explodes, it produces a large amount of gases, which further increases the pressure exerted on its surroundings. This high-pressure shockwave causes significant damage to buildings and structures.

4. Easy to manufacture: TNT is relatively easy and cheap to manufacture, making it a popular explosive for military and industrial applications.

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Answer: it holds two atoms together in a molecule. During a chemi- cal reaction, some of the bonds in the original molecule break. New bonds form to produce a new substance.

Explanation:

Answer:

2 atoms are held together in a molecule?

Explanation:

Hi, you've asked an incomplete question. However, I assumed you are referring to the article found on the Scientific American website.

Explanation:

Remember, according to that article we are told that scientists notice that these insects have a long nymphal (immature form before becoming adults) stage, one that can last up to 13 to 17 years on the ground before they leave the ground looking for mating partners.

Because it is only after mating occurs at this point that their eggs are laid, that is why scientists believe that cicadas only reproduce every 13 or 17 years.

Answer:

1.89

Explanation:

238cal = J joules

450cal = xJ joules

\( \frac{450}{238} = \frac{xj}{j} \)

1.89 = x

450cal = 1.89J joules

The density of an object = 5 g/ml

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

The unit of density can be expressed in g/cm³ or kg/m³  

Density formula:  

\(\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}\)

ρ = density  

m = mass  

v = volume  

Mass = 50 g

Volume of the object =

\(\tt 40-30=10~ml\)

So the density :

\(\tt \rho=\dfrac{50}{10}\\\\\rho=\boxed{\bold{5~g/ml}}\)

Taking into account the definition of calorimetry, the correct answer is the third option:  The heat exchanged is 10,450 J.

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

The amount of heat (Q) necessary to vary the temperature of a mass (m) of a substance is proportional to the change in its temperature (∆T) and to that mass. So, the equation that allows calculating heat exchanges is:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

Replacing in the expresion for calorimetry:

Q = 4.18\(\frac{J}{gC}\)× 100 g× 25 C

Solving:

Q= 10,450 J

Finally, the correct answer is the third option:  The heat exchanged is 10,450 J.

Learn more:

The reaction between NiCl2 and Fe is a single replacement reaction. A single replacement reaction involves an element reacting with a compound to produce a new element and a new compound. This reaction follows the general equation; A + BC → AC + B.

The activity series of metals will be used to predict the products of a single-replacement reaction when NiCl2 reacts with Fe. Here are the steps involved in predicting the products of a single-replacement reaction; Steps to predicting the product of a single-replacement reaction: Identify the metal that is being displaced. Metals on the left of the activity series of metals are known to displace metals on the right of the series. This is because metals on the left are more active than those on the right.Look for the element that is being displaced. Fe is being displaced since Ni is higher than Fe in the activity series of metals. As a result, Fe will be replaced by Ni. Identify the product. The Ni metal and Fe2+ will be produced by the reaction.

NiCl2(aq) + Fe(s) → Ni(s) + FeCl2(aq)

The balanced chemical equation will be

NiCl2 + Fe → FeCl2 + Ni

The reaction between NiCl2 and Fe is a single replacement reaction. A single replacement reaction involves an element reacting with a compound to produce a new element and a new compound. This reaction follows the general equation; A + BC → AC + B.

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ΔS∘ for Ti(s)+2Cl2(g)→TiCl4(g) is 659.6J/mol.. It is important to note that, as a general rule, a positive ΔS° indicates an increase in disorder and a negative ΔS° indicates a decrease in disorder.

The change in entropy (ΔS) for a chemical reaction can be calculated using the standard entropies (S°) of the reactants and products.

ΔS° = S°(products) - S°(reactants). For the reaction Ti(s) + 2Cl2(g) → TiCl4(g)S° of Ti(s) = 29.1 J/mol·K, S° of Cl2(g) = 223.1 J/mol·K, S° of TiCl4(g) = 167.4 J/mol·K. Therefore, ΔS° = (S°(TiCl4) + 2S°(Cl2)) - S°(Ti)ΔS° = (167.4 + 2*223.1) - 29.1 = 659.6 J/mol·K. So the ΔS∘ for Ti(s) + 2Cl2(g) → TiCl4(g) is 659.6 J/mol·K with four significant figures. It is important to note that, as a general rule, a positive ΔS° indicates an increase in disorder and a negative ΔS° indicates a decrease in disorder. So in this case, the process of going from solid titanium and gaseous chlorine to gaseous titanium tetrachloride increases disorder, which is consistent with a positive ΔS°.

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The concentration of this magnesium chloride solution when the reaction described in part a required 3.92 l of magnesium chloride is 0.451 M

M(AgNO3)=0.18 M

V(AgNO3)=1.92 L

V(MgCl2)=3.83 L

According to the balanced reaction:

We can write as follows;

1*number of mol of AgNO3 =2*number of mol of MgCl2

1*M(AgNO3)*V(AgNO3) =2*M(MgCl2)*V(MgCl2)

1*0.18*1.92 = 2*M(MgCl2)*3.83

M(MgCl2) = 0.0451 M

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Answer:

the atomic number of the element with 77 as atomic weight and 55 neutrons is 22

Answer: 47 p+, 107 n, 48 e–

Explanation:

Answer: An object's speed and motion can be changed by a force acting on it. This is described by Newton's Second Law of Motion, which states that the acceleration of an object is directly proportional to the force applied to it, and inversely proportional to its mass. Therefore, the greater the force applied to an object, the greater its acceleration will be, and the greater the change in speed or motion will be. Additionally, the direction of the force also plays a role in changing an object's motion, as it can cause the object to change direction or rotate.

Your welcome (:

Explanation:

NaF is an ionic compound. Between Na and F, an ionic connection is created, with Na losing one valence electron to become Na+ and F gaining one electron to produce F. NaF has an ionic connection as a result.

A chemical compound known as an ionic compound is one that contains ions bound together by the electrostatic forces known as ionic bonding. Despite having both positively and negatively charged ions known as cations and anions the molecule is generally neutral.

Between a metal and a non-metal, ionic bonding form. Ionic bonds, as opposed to covalent ones, involve the transfer of valence electrons between atoms. The non-metal atom receives the electrons that belong to the metal atom.

Here, sodium gives its one electron to fluorine, creating an ionic link between the two elements. Electrovalent bond is another name for an ionic bond.

Thus, NaF is an electrovalent or ionic compound as a result.

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HFO-1234yf has been tested and found compatible with  PAG oil.
The correct answer is option A. PAG oil

PAG oil, or Polyalkylene Glycol, is a fully synthetic hygroscopic oil specifically designed for automotive air conditioner compressors. It is used in R-134a air conditioning systems to lubricate the compressor. When looking at PAG oil you will notice various numbers such as PAG46 or PAG100. These numbers refer to the viscosity of the oil, similar to 10W30 oil. In order to determine the correct PAG viscosity for your vehicle you will need to look up the specifications of your make and model of your vehicle either online or in the instruction manual.

Hence, HFO-1234yf is compatible with PAG oil. It is not compatible with mineral oil, hydraulic oil, or all of the items listed.

The correct answer is option A. PAG oil.
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The heat involved in the dissolution of KCl is 2.29 kJ.

The amount of heat released or absorbed by a chemical reaction can be calculated using the formula: q = mCΔT, where q is the heat released or absorbed, m is the mass of the substance, C is the specific heat capacity, and ΔT is the change in temperature. In this case, the mass of KCl is 3.00 g and the change in temperature is 1.55 °C. The specific heat capacity of water is 4.18 J/(g·°C). We can convert the mass of KCl to moles by dividing by its molar mass of 74.55 g/mol. The resulting ΔH is -2.29 kJ/mol

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(i) The initial-boundary value problem for the given scenarios are as follows:

a) Scenario a:

PDE: ∂u/∂t = k * ∂²u/∂x²

Initial condition: u(x, 0) = 100 (boiling water temperature)

Boundary conditions: u(0, t) = 10, u(L, t) = 10 (constant temperature at the ends)

b) Scenario b:

PDE: ∂u/∂t = k * ∂²u/∂x²

Initial condition: u(x, 0) = 100 (boiling water temperature)

Boundary conditions: u(0, t) = 0 (temperature at x=0), ∂u/∂x(L, t) = 0 (thermal insulation at x=L)

(iii) The solution for the temperature distribution as time approaches infinity can be found by solving the appropriate steady state equation.

(i) The initial-boundary value problem formulation states the partial differential equation (PDE) governing the temperature distribution in the aluminum bar, along with the initial condition and boundary conditions.

In scenario (a), both ends of the bar are immersed in a medium with a constant temperature of 10 degrees Celsius, while in scenario (b), the end at x=0 is immersed in a medium with temperature 0 degrees Celsius and the end at x=L is insulated.

(ii) As time approaches infinity, the temperature distribution in the bar tends to reach a steady state.

In scenario (a), the temperature throughout the bar will eventually approach a constant value of 10 degrees Celsius, since both ends are immersed in a medium with that temperature.

In scenario (b), the temperature at x=0 will approach 0 degrees Celsius, while the temperature at x=L will remain constant due to thermal insulation.

(iii) To find the solution as time approaches infinity, we need to solve the appropriate steady state equation.

In scenario (a), the steady state equation is ∂²u/∂x² = 0, which implies that the temperature gradient is zero throughout the bar, resulting in a constant temperature of 10 degrees Celsius.

In scenario (b), the steady state equation is ∂²u/∂x² = 0 with the boundary condition u(0) = 0, which implies a linear temperature distribution from 0 degrees Celsius at x=0 to a constant temperature at x=L due to insulation.

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The reading on the vernier caliper is determined by adding main scale and vernier scale reading.

The diameter of a piece of wire can be measured using Vernier caliper.

The following steps can be used to measure the diameter of the Vernier caliper;

Thus, the reading on the vernier caliper is determined by adding main scale and vernier scale reading.

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