I’m having trouble with this assignment please help.

Answer:

If I am correct the last one because the pressure is decreasing and the temperature is increasing

Answer:

When you are going to measure small lengths or objects or when you are going to measure things with great accuracy.

Explanation:

Answer:

The correct answer is 24.31 amu.

Explanation:

The formula for finding the average atomic mass = The sum of the percentage abundance of isotopes × the actual mass of isotopes

The average atomic mass = % abundance of Mg-24 × actual mass + % abundance of Mg-25 × its actual mass + % abundance of Mg-26 × its actual mass

Avg. Atomic mass = 0.7870 × 23.98504 + 0.1013 × 24.98584 + 0.1117 × 25.98259

Avg. atomic mass = 18.88 + 2.53 + 2.90 = 24.31 amu

The atomic mass of magnesium is 24.31 amu.

Answer:  81.7 ml

Explanation:  

1 cm^3 = 1 ml

Divide the total mass by it's density to find it's volume:

(52.4g/7.87g/ml) = 6.658 ml

Add to 75.0 ml to arrive at a final volume of 81.7 ml

Answer:

Group number – 8

Explanation:

To determine the charge on the ion formed by various elements, we simply consider their valence electrons.

However, this is only applicable to elements in group 1, 2 and 3 only.

To determine the charge on the ions formed by non metals i.e elements in group 4, 5, 6, 7 and 8(group 0) we simply subtract 8 from the group number i.e group number – 8

This can be further explained as follow:

Chlorine belong to group 7 because it has 7 valence electrons.

The charge on the chloride ion can be obtained as follow:

Group number = 7

Charge on ion =?

Charge on ion = Group number – 8

Charge on ion = 7 – 8

Charge on ion = – 1

Therefore, the charge on chloride ion is – 1.

Answer:

electronegativity increases

Answer:

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Answer:

Explanation:

Two sig digits means that 5239 becomes 52 with some zeros behind it. How many?

There were 2 numbers after the 2. So two sig digits would become 5200

If the third digit from the left is a 5 or more then the answer would be

5300.

Answer: bạn viết phương trình Phenol + NaOH

=> nNaOH = nPhenol = 0,2 mol

m Phenol = 0,2x94 = 18,8 gam

%mPhenol = 18,8/28,9% = 65,05

Explanation:

Answer:

Photometer

Explanation:

A photometer (photo comes from the Greek for light) measures the light coming from 140,000 stars in Kepler's stationary field of view. If a planet transits (passes in front of) any star the amount of light from the star is reduced enough so that the photometer senses it and relays the information back to the Kepler team.

Scientific instruments are tools used for researching the universe and natural sciences. A Photometer is sensitive enough to detect a planet transiting a star. Thus, option D is correct.

A Photometer is a device that converts light energy into electrical voltage by the photoelectric effect given by Einstein. It uses Quantum mechanics to convert the energy possessed by the photons and electrons. It follows Ohm's law to convert energy.

It is used to detect the planets transiting stars as they can detect the light energy as it uses the electromagnetic radiation of various wavelengths to convert them by the photodiode, resistor, and a multiplier.

Therefore, option D. a photometer is used to detect the planets in the universe transiting stars.

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Your question is incomplete, but most probably your full question was, What scientific instrument is sensitive enough to detect a planet transiting a star?

Answer:

okay I will help you

Explanation:

okay

Answer:

question?

Explanation:

Respuesta:

21.8 L

Explicación:

Paso 1: Escribir la reacción balanceada

CaCO₃ ⇒ CaO + CO₂

Paso 2: Convertir 450 g de CaCO₃ a moles

La masa molar de CaCO₃ es 100.09 g.

450 g × (1 mol/100.09 g) = 4.50 mol

Paso 3: Calcular los moles de CO₂ que se forman a partir de 4.50 moles de CaCO₃

La relación molar de CaCO₃ a CO₂ es 1:1. Los moles de CO₂ formados son 1/1 × 4.50 mol = 4.50 mol.

Paso 4: Convertir la temperatura a Kelvin

Usaremos la siguiente expresión.

K = °C + 273.15 = 200°C + 273.15 = 473 K

Paso 5: Calcular el volumen de CO₂

Usaremos la ecuación del gas ideal.

P × V = n × R × T

V = n × R × T / P

V = 4.50 mol × (0.082 atm.L/mol.K) × 473 K / 8 atm

V = 21.8 L

Answer:

Reacting hydrogen and oxygen gases to make water

Explanation:

Exothermic means that energy is released into the environment, so let's go through the process of elimination.

Allowing meat to thaw after taking it out of the freezer - NO it is endothermic, and takes energy/heat from the environment to thaw.

Popsicle melting on a warm summer day - NO also endothermic, the opposite of exothermic.

Boiling water in a beaker to convert it to steam - NO because we need to add heat, so it doesn't release any energy.

Rolling a ball up a hill - NO, for a ball to roll up a hill, it needs energy from something else, so it's not exothermic.

Reacting hydrogen and oxygen gases to make water - YES this reaction makes new bonds, which releases energy, so this is exothermic.

Among the following choices reacting hydrogen and oxygen gases to make water is an exothermic reaction as it releases energy as new bonds are formed.

An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.

In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.

Examples of exothermic reactions are combustion reactions, detonation of nitroglycerin , neutralization reactions and nuclear fission.

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Answer:

Determine the volume of helium gas

Answer:

About 1,495 Liters of Helium.

Explanation:

To calculate the volume of helium gas formed when the magnet loses its superconducting properties, we can use the ideal gas law:

PV = nRT

Where:

P = Pressure (in atm)

V = Volume (in liters)

n = Number of moles of helium gas

R = Ideal gas constant (0.0821 L.atm/(mol.K))

T = Temperature (in Kelvin)

First, we need to find the number of moles of helium gas:

Given volume of liquid helium (V_liquid) = 1950 L

Density of liquid helium (ρ) = 0.125 g/mL = 0.125 g/cm³

To convert density from g/cm³ to g/L, we multiply by 1000:

Density of liquid helium (ρ) = 0.125 g/cm³ * 1000 cm³/L = 125 g/L

Mass of liquid helium (m) = Volume * Density = 1950 L * 125 g/L = 243,750 g

Next, we need to convert the mass of liquid helium to moles using the molar mass of helium:

Molar mass of helium (M) = 4.0026 g/mol

Number of moles (n) = Mass / Molar mass = 243,750 g / 4.0026 g/mol ≈ 60,907 mol

Now, we have the number of moles of helium gas (n), and we can calculate the volume of helium gas (V_gas) at 25°C (298.15 K) and 1 atm:

P = 1 atm

T = 25°C = 298.15 K

V_gas = nRT / P

V_gas = (60,907 mol) * (0.0821 L.atm/(mol.K)) * (298.15 K) / (1 atm)

V_gas ≈ 1,495 L

Therefore, approximately 1,495 liters of helium gas would be formed at 25°C and 1 atm when the magnet loses its superconducting properties.

Elements which have high electron negativity are more reactive than elements with low electron negativity.

This is because elements with high electron negativity will gain more electrons to become more stable.

When electron negativity of an element decrease it becomes more into its element form.

There will be more ionization energy of the elements who have more electron negativity.

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Answer:     An element will be more reactive if it has a very high or very low electronegativity.  

Is your answer

Answer: Technician B

Explanation:

Technician B is correct. The freezing point of a substance is the temperature at which the substance changes state from a liquid to a solid.

Technician A is incorrect. On the other hand, the melting point of a substance is the temperature at which the substance changes state from a solid to a liquid.

the answer is highly possible to be C

Prefixes are used to indicate the number of atoms in both

covalent and ionic compounds.

Covalent or molecular compounds form when elements share electrons in a covalent bond to form molecules. Molecular compounds are electrically neutral.

Ionic compounds are (usually) formed when a metal reacts with a nonmetal (or a polyatomic ion). Covalent compounds are formed when two nonmetals react with each other. Since hydrogen is a nonmetal, binary compounds containing hydrogen are also usually covalent compounds.

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it might be porous materials

Answer:

Air had the highest rate of absorption.  Air absorbs most of the suns heat and sun rays and air can move to different areas which are warm and colder.

Explanation:

Answer: broooo what is this

Explanation:

Answer:

rabbit

Explanation:

Answer:

rabbit

Explanation:

the rabbit is the consumer because the sun "produces" the tree and mushroom, the rabbit comes along and eats the mushroom which was produced by the sun.

Answer:

The body stores lipids ingested as fat and uses this energy when needed-chemical energy

A person's hat falls off and lands on the ground- gravitational energy

A wave of water pushes a surfer to shore- mechanical energy

A burner on a stove heats up a tea kettle- thermal energy

A power plant splits atoms to generate power for a city- nuclear energy

A nerve sends an impulse to another nerve- electrical energy

A plant absorbs the Sun's rays to start the process of photosynthesis- radiant energy

Explanation:

Gravitational energy is energy stored by an object as a consequence of its height.

Mechanical energy is the energy that is possessed by an object due to its motion or due to its position.

Chemical energy refers to energy stored in chemical bonds in a substance.

Thermal energy is a form of energy that exists due to temperature difference between two bodies.

Nuclear energy refers to energy stored in the nucleus of an atom.

Electrical energy is a form of energy resulting from the flow of electric charge.

Radiant energy refers to energy that moves through vacuum without passing through a material medium.

Answer:

Explanation:

given mass on earth =98 kg

gravitational pull on mars =3.711 m/s2

gravitational pull on venus =8.87 m/s2

weight of the body on mars =weight on earth/9.81 m/s2 *3.711 m/s2

W=98 kg*3.711 /9.81m/s2

W=37.07 kg

weight on the venus =weight on earth*8.87 m/s2 /9.81 m/s2

W= 98 kg*7.87 m/s2/9.81 m/s2

W=78.62 kg

Answer:

A base releases OH~ in a solution, so the answer is B

Answer:

CO32−

Explanation:

We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.

When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;

2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)

Answer:

A).  CO32−

Explanation:

Answer:

88

Explanation:

The ion has a charge of 2+, therefore the number of neutrons it possess is 86+2

which equals 88

The element X having a mass number of 230 and has 86 electrons is radium and has  142 neutrons.

An atom is composed basically of electrons, protons and neutrons. In a neutral atom, the number of protons and electrons are equal. The number of neutrons is the difference between the mass number and the number of protons (atomic number).

Since we know that the ion of the element X has 86 electrons and the compound formed is XBr2, it then means that neutral X has 88 electrons.

The number of electrons in the neutral atom is the same as the number of protons or atomic number. An element can be identified by its atomic number. The element having atomic number 88 is radium.

The number of neutrons is obtained as;

Mass number - atomic number

230 - 88 = 142 neutrons

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Answer: [tex]1409.55[/tex]

Remove the 0's from each decimal number

[tex]3.7500 ---> 3.75\\9.7100 ---> 9.71[/tex]

Multiply

[tex]3.75*104=390\\9.71*105=1019.55[/tex]

Add

[tex]930+1019.55=1409.55[/tex]

Answer:

[tex]\rm MgBr_2 \cdot 6\, H_2O[/tex].

Explanation:

Let [tex]x[/tex] denote the number of [tex]\rm H_{2}O[/tex] formula units for every [tex]\rm MgCl_{2}[/tex] formula unit. The formula of the hydrate would be [tex]{\rm MgBr_2} \cdot x\, {\rm H_2O}[/tex].

Look up the relative atomic mass of each element on a modern periodic table:

Formula mass:

[tex]\begin{aligned}M({\rm MgBr_{2}}) &= 24.305 + 2 \times 79.904 \\ &= 184.113\; \rm g\cdot mol^{-1}\end{aligned}[/tex].

[tex]\begin{aligned}M({\rm H_{2}O}) &= 2 \times 1.008 + 15.999 \\ &= 18.015\; \rm g\cdot mol^{-1}\end{aligned}[/tex].

The anhydrous compound would be [tex]\rm MgBr_{2}[/tex]. There was [tex]27.21\; \rm g[/tex] of this compound. Calculate the number of moles of formula units in that much of this compound:

[tex]\begin{aligned}n({\rm MgBr_{2}}) &= \frac{m({\rm MgBr_{2}})}{M({\rm MgBr_{2}})} \\ &= \frac{27.21\; \rm g}{184.113\; \rm g \cdot mol^{-1}} \\ &\approx 0.1478\; \rm mol\end{aligned}[/tex].

During heating, [tex]43.19\; \rm g - 27.21\; \rm g = 15.98\; \rm g[/tex] of water [tex]\rm H_{2}O[/tex] escaped from the hydrate. Calculate the number of formula units in that [tex]15.98\; \rm g[/tex] of [tex]\rm H_{2}O\![/tex]:

[tex]\begin{aligned}n({\rm H_{2}O}) &= \frac{m({\rm H_{2}O})}{M({\rm H_{2}O})} \\ &=\frac{43.19\; \rm g - 27.21\; \rm g}{18.015\; \rm g \cdot mol^{-1}} \\&= \frac{15.98\; \rm g}{18.015\; \rm g \cdot mol^{-1}} \\ &\approx 0.887\; \rm mol\end{aligned}[/tex].

In other words, approximately [tex]0.1478\; \rm mol[/tex] of [tex]\rm MgBr_{2}[/tex] formula units (and hence the same number of moles of [tex]{\rm MgBr_2} \cdot x\, {\rm H_2O}[/tex] formula units) contain approximately [tex]0.887\; \rm mol[/tex] of [tex]\rm H_{2}O[/tex] formula units. Calculate the ratio between the two:

[tex]\begin{aligned}x &= \frac{n({\rm H_{2}O})}{n({\rm MgBr_2})} \\ &\approx \frac{0.1478\; \rm mol}{0.887\; \rm mol} \approx 6\end{aligned}[/tex].

Hence, the formula of the hydrate would be [tex]\rm MgBr_2 \cdot 6\, H_2O[/tex].

Answer: The new relative charges between two atoms are +1 and -1 for cation and anion respectively.

Explanation:

When an atom accepts an electron, negative charge is created on atom and is called as anion.

When atom loses an electron, positive charge is created on atom and is called as cation.

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

Thus when one electron is lost by an atom it forms one positive charge and when one electron is gained by an atom it forms one negative charge.

Foe example: sodium atom loses its one valance electron and form cation [tex]Na^+[/tex]. Chlorine atom gain one electron and form anion [tex]Cl^-[/tex].  they both combine to form sodium chloride through ionic bond.

Answer:

A. acidic

Explanation:

Citrus fruits may taste sour because they are acidic. They have citric acid and ascorbic acids.

Hey there!:

Mass = 0.6 g

Density = 0.0012 g/mL

Volume = ??

Therefore :

Density = mass / Volume

0.0012 = 0.6 / V

V = 0.6 / 0.012

V = 500 mL

Hope this helps!