How does the appearance of a substance change when it
changes phase?

Answer: see below

Explanation:

Mg burning in air gives MgO and a smaller amount of Mg3N2

2Mg+O2=2MgO. 2*24.3+32=2*40.3

3Mg+N2=Mg3N2

Ignoring the nitride, MgO loss of mass during the reaction can be ascribed to

(1) relativistic loss as energy (too small to be measurable)

(2) During the reaction, which is strongly exothermic, a fraction f the material is blown off as tiny particles which adhere to the vessel.

Answer:

d.

Explanation:

the electricity is why we can hear sounds from the television and see it

Answer:

water

Explanation:

water is made up of both hydrogen and oxygen (h2o)

Answer:

Boiling Water

Explanation:

Boiling water is an example of physical change and not and not a chemical change because the water vapor still has the same molecular structure as liquid water.If the bubbles were caused by the decomposition of a molecule into gas then boiling would be a chemical change.

Answer:

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding

Explanation:

Answer:

No. of moles = 0.0685

Explanation:

Given mass, m = 15.5g

We need to find the number of moles in 15.5 g of CaSO₄.5H2O

First, we find the mass of CaSO₄.5H2O.

M = (1×40)+(1×32)+(4×16)+(5×18)

M = 226 g/mol

We know that,

Number of moles = given mass/molar mass

[tex]n=\dfrac{15.5\ g}{226\ g/mol}\\\\n=0.0685\ \text{mol}[/tex]

Hence, there are 0.0685 moles in 15.5 g of CaSO₄.5H2O.

Answer:

5.13 g of CO₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

C₁₂H₂₂O + 17O₂ —> 12CO₂ + 11H₂O

Next, we shall determine the mass of C₁₂H₂₂O that reacted and the mass of CO₂ produced from the balanced equation. This can be obtained as follow:

Molar mass of C₁₂H₂₂O = 182 g/mol.

Mass of C₁₂H₂₂O from the balanced equation = 1 × 182 = 182 g

Molar mass of CO₂ = 12 + (2×16)

= 12 + 32

= 44 g/mol

Mass of CO₂ from the balanced equation = 12 × 44 = 528 g

SUMMARY:

From the balanced equation above,

182 g of C₁₂H₂₂O reacted to produce 528 g of CO₂.

Finally, we shall determine the mass of CO₂ produced from the reaction. This can be obtained as follow:

From the balanced equation above,

182 g of C₁₂H₂₂O reacted to produce 528 g of CO₂.

Therefore, 1.77 g of C₁₂H₂₂O will react to produce = (1.77 × 528)/182 = 5.13 g of CO₂.

Thus, 5.13 g of CO₂ were obtained from the reaction.

Answer:

55.6 °C

Explanation:

From the question given above, the following data were obtained:

Mass (M) of diamond = 32.0 g

Initial temperature (T₁) = 33.5°C

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Final temperature (T₂) =?

Next, we shall determine the change in temperature. This can be obtained as follow:

The final temperature can be obtained as follow:

Mass (M) of diamond = 32.0 g

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Change in temperature (ΔT ) =?

Q = MCΔT

360 = 32 × 0.509 × ΔT

360 = 16.288 × ΔT

Divide both side by 16.288

ΔT = 360 / 16.288

ΔT = 22.1 °C

Finally, we shall determine the final temperature. This can be obtained as follow:

Initial temperature (T₁) = 33.5°C

Change in temperature (ΔT ) = 22.1 °C

Final temperature (T₂) =?

ΔT = T₂ – T₁

22.1 = T₂ – 33.5

Collect like terms

22.1 + 33.5 = T₂

T₂ = 55.6 °C

Therefore, the final temperature is 55.6 °C.

The food has 23629.64 cal

Given

mass = 1000 g of water

temperature increases 23.65 * C

Required

The energy of the food

Solution

Heat absorbed by water :

Q = m . c . Δt

Q = 1000 g x 4.184 J/g°C x 23.65 °C

Q = 98951.6 J

1 Joules = 0.2388 Calories

98951.6 J = 23629.64 cal

Answer:

its less negative hope I helped buster

Because trans isomers are more stable than cis isomers, the cis isomer will have a less negative heat of formation than the trans isomer.

Cis- and trans isomers are compounds that have different configurations in space because of the presence of a rigid structure or functional groups in their molecule.

Cis atoms have functional groups on the same side.

Trans isomers have functional groups on alternate different.

The structure of cis-1-bromor-2-butene is attached.

Generally, trans isomers are more stable than cis isomers..

Stable compounds have more negative heat of formation while unstable compounds have less negative heat of formation.

Therefore, the cis isomer will have a less negative heat of formation than the trans isomer.

Learn more about cis and trans isomers at: https://brainly.com/question/4625349

sorry i can only figure out 1 but the answer is

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124

hope you do good on your test :D

Answer:

Acid Phosphatase (AP) Test

Explanation:

Acid phosphate is an enzyme that is found in the body. It is secreted majorly by the prostrate gland into the seminal fluid. The acid phosphatase test is used to test for the presence of semen in items.

Scott chose the acid phosphatase test because it is very useful in testing for semen on large items such as blankets. The reaction time for an acid phosphatase test for semen is less than 30 seconds. Seeing that the test was completed in three minutes, Scott concluded that the positive reaction was as a result of some other fluid.

The detectives reported that an overturned bowl of grapes and watermelon was found at the scene as well as a broken glass that had contained wine. Scott knew that some fruit juices like that of watermelon give a positive reaction to the acid phosphatase test but with  more time that of the semen fluid because the reaction is a very slow one.

Scott concluded that there was no presence of semen on the blanket and therefore there was no sexual assault.

Answer:

See explanation and image attached

Explanation:

The  Gilman reagent is a lithium and copper (diorganocopper) reagent with a general formula R2CuLi.  R is an alkyl or aryl group.

They are useful in the synthesis of alkanes because they react with organic halides to replace the halide group with an R group.

In this particular instance, we intend to synthesize propylcyclohexane. The structure of the  lithium diorganocopper (Gilman) reagent required is shown in the image attached to this answer.

Answer:

Option C

Explanation:

The answer is option C or "The amount of time it takes to rotate around it's axis is the same amount of time it takes to revolve around Earth."Remember that the Earth and the Moons amount of time to make a full rotation is almost in sync and they're two sides of the moon, one side we do not see and that's because that side is currently faced away from the Earth which is called the dark side of the moon. Each side has two weeks oh night, and two weeks of day because of how long it takes the moon to revolve, so while we have a side towards the Earth which is illuminated by the sun we have another pointing away in the dark.

Hope this helps.

Answer:

The system releases energy to the environment, because its internal energy decreases.

The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.

The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.

The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.

Explanation:

Now we know that when a reaction is exothermic heat is given off. In this case, we have a reaction that connects the ends of a chain of carbons to form a ring.  The bonding electrons now move into a lower energy bonding sigma molecular orbital.

This leads to a decrease in the entropy and enthalpy of the system because energy is given off, the closure of the ring reduces the number of conformations the ring can adopt and  the electrons that form the bond enter an orbital that is at a lower energy.

The entropy of the surroundings is increased as energy is given out. The surroundings absorb heat released by the reaction, and become more disordered.

Answer:

50g

Explanation:

At the end of the burning process, the mass of the jar and smoke should be 50g after the candle burning is done.

In most systems, the law of conservation of matter finds expression. According to this law "matter is neither created nor destroyed but atoms are rearranged".

In this kind of system, no matter is allowed to escaped and the starting mass of the reactants compared to that of the product will be the same.

Answer:

an aquifer is a renewable resource

Explanation:

Aquifers are defined as the groundwater found deep in the layers of rocks.

An aquifer is considered as a renewable resource because groundwater is renewed over time. Aquifers are water resources and follow hydrological cycle through which it can renew itself.

Some of the deep aquifers are considered as  nonrenewable resource because it toll hundreds of years to accumulate.

Hence, the correct answer is yes an aquifer is a renewable resource except some deep aquifers.

Answer:

b or c

Explanation:

Answer:

Covalent-network (also called atomic) solids—Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes.

I hope it's helpful!

Answer:

network solid

Explanation:

Answer: FeF3      Iron(III) fluoride

Explanation: 5.6 g = 1/10 mole Fe

11.3-5.6g F = 5.7 = 3/10 mole F

Answer:

1. aa

2. They have similar DNA

Explanation:

1. According to the question 1, wrinkled seeds (A) are dominant over round seeds (a) in pea plants. This means that, based on the law of dominance proposed by Mendel, wrinkled seeds will be expressed over round seeds in a heterozygous state (Aa).

However, since the round seed phenotype is a recessive trait, it will only be expressed when the alleles for round seeds (a) are the same in the gene i.e. aa genotype.

2. Based on the information in question 2, Ricky, who is working on a family tree for his school project, realizes that his close relatives all look similar in the pictures he collected. This is possible because of the SIMILARITY OF THEIR DNA (genetic material). Note that, relatives are connected by the genes that are inherited from one another, hence, they possess a similar DNA, which is the most valid reason for the resemblance.

Answer:

The anwer is not D the anwer is A

Explanation:

Answer:

A. 2 He

Explanation:

The notation of an alpha particle is depicted as:

                     ₂He

An alpha particles is a nucleus of 2 protons and 2 neutrons. So it is actually a Helium cation.

Alpha particles are monoenergetic and they mostly have discrete energy.

So, the mass number of the particle is 4 and atomic number is 2

Answer:

4d orbital.

Explanation:

Hello!

In this case, since zirconium's atomic number is 40, we fill in the electron configuration up to 40 as shown below:

[tex]1s^2,2s^2,2p^6, 3s^2,3p^6,4s^2,3d^{10},4p^6,5s^2,4d^2[/tex]

Thus, the orbital 4d is partially filled.

Best regards!

Answer:

Krypton

Explanation:

Answer: The correct order of coefficients is 4, 5, 4 and 6.

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side.

The balanced chemical equation is:

[tex]4NH_3+5O_2\rightarrow 4NO+6H_2O[/tex]

The correct order of coefficients is 4, 5, 4 and 6.

Answer:

[tex]1.05x10^{24}atoms[/tex]

Explanation:

Hello!

In this case, according to the definition of the Avogadro's number, it is possible to realize that one molecule of CO2 contains 3 moles of atoms, one of carbon and two of oxygen, thus, we have:

[tex]0.580molCO_2*\frac{3mol\ atoms}{1molCO_2} =1.74mol\ atoms[/tex]

Then, we use the Avogadro's number to obtain:

[tex]1.74mol\ atoms*\frac{6.022x10^{23}atoms}{1mol\ atoms} \\\\1.05x10^{24}atoms[/tex]

Best regards!

The specific heat : c = 0.306 J/g K

Given

Heat = 35.2 J

Mass = 16 g

Temperature difference : 7.2 K =

Required

The specific heat

Solution

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

Input the value :

c = Q / m.∆T  

c = 35.2 / 16 x 7.2

c = 0.306 J/g K