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Answer:

the correct answer is A

Explanation:

I took the test!

Answer:

A probably because its ionic

Answer:

Ammonium chloride and slacked lime

Explanation:

We can generate ammonia gas in the research centre by slowly heating ammonium chloride (NH4Cl) and slaked lime [Ca(OH)2]. Ammonia gas is lighter than air, requiring its accumulation by the descending displacement of air.

Answer:

One element takes the place of another in a compound

Explanation:

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Answer:

Approximately [tex]41.2\; {\rm ^{\circ} C}[/tex].

Explanation:

Let [tex]t\; {\rm ^{\circ} C}[/tex] be the final temperature of the water and the iron.

Temperature of the water would be increase by [tex](t - 38.00)\; {\rm ^{\circ} C}[/tex].

Temperature of the iron would be reduced by [tex](100.0 - t)\; {\rm ^{\circ} C}[/tex].

Let [tex]c[/tex] denote the specific heat of each material. Let [tex]m[/tex] denote the mass of the material. For a temperature change of [tex]\Delta t[/tex], the energy change involved would be:

[tex]Q = c\, m \, \Delta t[/tex].

The energy that the water need to absorb would be:

[tex]\begin{aligned}& Q(\text{water, absorbed}) \\ =\; & c(\text{water}) \, m(\text{water})\, \Delta t (\text{water}) \\ =\; & 4.181\; {\rm J \cdot g^{-1} \cdot K^{-1}} \times 50\; {\rm g} \times (t - 38.00)\; {\rm ^{\circ} C} \\ =\; & (209.05\, t - 7943.9)\; {\rm J} \end{aligned}[/tex].

The energy that the iron would need to release would be:

[tex]\begin{aligned}& Q(\text{iron, released}) \\ =\; & c(\text{iron}) \, m(\text{iron})\, \Delta t (\text{iron}) \\ =\; & 0.45\; {\rm J \cdot g^{-1} \cdot K^{-1}} \times 25.0\; {\rm g} \times (100.0 - t)\; {\rm ^{\circ} C} \\ =\; & (1125 - 11.25 \, t)\; {\rm J} \end{aligned}[/tex].

Since this calorimeter is insulated, the energy that the iron had released would be equal to the energy that the water had absorbed:

[tex]Q(\text{water, absorbed}) = Q(\text{iron, released})[/tex].

[tex]209.05\, t - 7943.9 = 1125 - 11.25\, t[/tex].

[tex]t \approx 41.2[/tex].

Thus, the final temperature of the water and the iron would be approximately [tex]41.2\; {\rm ^{\circ} C}[/tex].

Answer:

Zinc (Zn) will safely react with dilute sulphuric acid.

Explanation:

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Answer:

2 ATP molecules are produced

Answer:

2 ATP molecules of ATP are produced

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Answer:

0.1 M

Explanation:

(25 mL) (0.20 M) / 50 mL = 0.1 M

Answer:

b. because its Rigel star

Explanation:

hope itsattachments

Answer:

Technetium. It is only found in the stars.

Explanation:

Sorry, but thats all I could find for tou

The are many elements which are not present in human body. But almost all the discovered elements are there in the universe. But the one which is not present in earth and air is technetium

Technetium  is the first synthesized element by man in 1937. Technetium has no stable isotopes and it is not found in earth. But it is present in stars. However, rare earth elements such as promethium , francium etc. can be prepared or observed from uranium ores.

There are many elements especially  some actinides and lanthanides which are not present in earth naturally existence on starts and other planets.

Human body is made of various elements including carbon, oxygen, nitrogen, various metals like iron, zinc etc.  Various enzymes contains different elements but the number of elements which are in the surroundings of human and not inside is larger.

Therefore, all the discovered elements are found in the universe and some them are not present in earth.  

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Answer:

I think its a homogeneous mixture (pls correct me if im wrong)

Explanation:

It is a homogeneous mixture because its an alloy made of gold, silver, copper, and other metals that are melted together. A homogeneous mixture is composed of a uniform composition of particles.

There are two types of mixture, one is homogeneous mixture and other is heterogeneous mixture. Therefore, the term best describes 10-karat gold is homogeneous mixture.

When two or more compounds are combined but each ingredient retains its chemical identity, the result is referred to as a mixture. In other words, there is no chemical interaction between the parts of a combination. According to how consistent they are and how well the components' particle sizes match up, mixtures are categorized.

Because it is an alloy comprised of melted gold, silver, copper, and other metals, it is a homogenous combination. A homogeneous mixture has a consistent distribution of its constituent particles.

Therefore, the term best describes 10-karat gold is homogeneous mixture.

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Using the Rydberg formula, the spectral line of H - atom is suitable for this purpose is Paschen, ∞ → 3.

1/λ = RH(1/nf^2 - 1/ni^2)

Given that;

λ = wavelength

RH = Rydberg constant

nf = final state

ni = initial state

Then;

1/λ =  1 × 10^7 m-1 (1/3^2 - 1/ ∞^2)

1/λ =  1 × 10^7 m-1 (1/3^2 )

λ = 900 nm

Hence, the correct answer is Paschen, ∞ → 3

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Answer:

B and C

Explanation:

Answer:

B) A dead tree rots on the ground.

C) A forest fire burns a lot of trees.

Explanation:

It cannot return the the state it was in before or have the same composition it had before.

Answer:

Carbon Dioxide is a non-flammable gas that extinguishes fire by displacing oxygen

CO2s are designed for Class B and C (flammable liquid and electrical) fires only.

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Answer:

Nomenclature is the process of naming chemical compounds with different names so that they can be easily identified as separate chemicals. ... For example, organic compounds include molecules with carbon rings and/or chains with hydrogen atoms (see picture below).01-Jul-2014

Nomenclature: Iron (II) Chloride

Compound: FeCl2

Answer:

1

Explanatio

right on edge

Among the given images, the one which is an example of non-renewable source of energy is image -1 the cooking gas is a petroleum product and it is non-renewable.

Non-renewable energy sources are sources of energy that come from finite resources that cannot be replenished on a human timescale. They are called non-renewable because their reserves are being depleted faster than they can be replenished. These energy sources include:

Fossil fuels: Coal, oil, and natural gas are the three main types of fossil fuels. They are formed over millions of years from the remains of plants and animals that lived long ago. Fossil fuels are currently the most widely used sources of energy for electricity generation, transportation, and industrial processes.

Nuclear energy: Nuclear energy is produced through the process of nuclear fission, which involves splitting atoms of uranium or plutonium to release energy. Nuclear power plants generate electricity using this process.

Non-renewable energy sources are a major contributor to greenhouse gas emissions, which contribute to climate change. As a result, there is a growing need to transition to renewable energy sources that are sustainable and have a lower environmental impact.

Here, image 1 - cooking gas is non-renewable.

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Answer:

compound

Explanation:

A compound contains more than one element.

Methane's chemical formula (CH4) indicates that it consists of one carbon atom and four hydrogen atoms.

Therefore, methane is a compound.

Answer:

It will be a covalent bond.

Explanation:

When two atoms combine, the difference between their electronegativities is an indication of the type of bond that will form. If the difference between the electronegativities of the two atoms is small, neither atom can take the shared electrons completely away from the other atom and the bond will be covalent.

Answer:

2-

Explanation:

Oxygen always act with an oxidation number of 2- unless we're talking of peroxide such as H2O2, where oxygen acts with an oxidation number of 1-

Answer:

Word equation: Potassium chlorate → Potassium chloride + Oxygen

Chemical equation: KClO₃ → KCl + O₂

Explanation:

This is decomposition reaction so there will only be one reactant, which is potassium chlorate.

The chemical equation will be:

KClO₃ → KCl + O₂

The balanced equation would be:

2KClO₃ → 2KCl + 3O₂

The word equation will be:

Potassium chlorate → Potassium chloride + Oxygen

Answer:

In many parts of the world, water taken directly from wells or public supplies is not safe to drink because it may carry waterborne parasites or other diseases. The water can be sterilized by boiling it, but fuel is needed to do so.

Explanation:

Answer:  Public water supplies are unsafe in some parts of the world because the water may carry bacteria.

Explanation:

The largest risks while designing a model to withstand a village include that the model does not mitigate the effects of the tsunami or only mitigates the effects partially, which would cause damages to the homes.

Designing a model to withstand the effect of any natural phenomenon such as an earthquake, fire or tsunami is not an easy task and will require the following cycle:

In the case of a model for tsunamis, it is likely the following problems occur:

This would lead to negative effects such as:

Note: This question is incomplete because the context is missing; here is the missing part.

Protecting Your Model Village from Tsunamis this task, you will design a model village to withstand the effects of a tsunami.

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Answer:

21. D (Food moves into the small intestine.)

22. C (Food is stored and further broken down by acid and powerful enzymes.)

23. A (Your saliva helps break down what you're eating and turn it into chemicals called enzymes.)

24. B (...Food moves through your esophagus.)

25. E (Anything left in the small intestine moves into the large intestine.)

Explanation:

Food first enters the mouth where it is chewed and broken down by salivary amylase. Then, it is swallowed, moving down the esophagus to the stomach where it is stored and further broken down by acids and enzymes. And, these broken down food molecules moves into the large intestine.

Answer:

To make H2O, you need two H and one O. in this equation, you are given two Os which is too many. you'll end up with an extra O. H2 + O2 -> H2O + O

Answer:

Alright, the first thing we have to do is to balance the chemical equation

2Na3N -----> 6Na + 1N2

We have 60g of Na3N, we convert them into moles by dividing the mass of the compound by the molar mass.

Molar mass of Na3N = (22.98 x 3) + (14) = 82.94g/mol

  60          =  0.72341451651 moles of Na3N

82.94

Now because we did the balanced equation, we know the mole to mole ratio of Na3N to N2 would be 2:1, so in order to get the moles of N2 you have to divide the moles of Na3N by 2

0.72341451651 moles/2 = 0.361707258 moles of N2

Now that we have the moles of N2, we just have to determine the mass of it in grams. In order to do that, just multiply the moles by the molar mass of N2 (28g/mol)

0.361707258 x 28 = 10.13g of N2

Therefore the decomposition of 60g of Na3N would result in 10.13g of N2 (nitrogen gas)