When 3.0 kg of water is warmed from 10 °C to 80 °C, how much heat energy is needed?

To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. The correct option is option C.

Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.

In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.

In the two figure the number of electrons in the outermost shell or valence shell is 2. The group of periodic table that has valency 2, is the alkaline earth metals. So, the group number, the two atoms have in common.

Therefore, the correct option is option C.

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Answerb

Explanation:because I got it right

Answer:

a) Density of unknown liquid = 0.934 g/cm³

b) Yes

c) The unknown liquid is methyl acetate

Note: The question is missing some parts; the densities of the liquids from the material data sheet. A similar question is given below:

A chemist working as a safety inspector finds an unmarked bottle in a lab cabinet. A note on the door of the cabinet says the cabinet is used to store bottles of acetone, chloroform, methyl acetate, glycerol, and ethanolamine.

The chemist plans to try to identify the unknown liquid by measuring the density and comparing to known densities. First, from his collection of Material Safety Data Sheets (MSDS), the chemist finds the following information: (the attachment below shows a table of the Material Safety Data Sheet)

Explanation:

Part 1

Density = mass/volume

Mass of unknown liquid = 512.0 g

Volume of unknown liquid = 0.548 L = 548 cm³ (Note: 1 L = 1000 cm³)

Density = 512.0 g/548 cm³ = 0.934 gcm³l to 3 significant figures.

Part 2

Yes, it is possible to identify the liquid from the value of its calculated density when compared with that of the known liquids in the Materials and Safety Data Sheet.

Part 3

The unknown liquid is methyl acetate since the density of the unknown liquid matches its density.

Answer:

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

From the question

volume of metal = 200 mL

density = 8.9 g/mL

We have

mass = 8.9 × 200

We have the final answer as

Hope this helps you

Answer:

O₂ = 0.141

CO = 0.282

CO₂ = 0.577

Explanation:

The reaction of graphite with Oxygen is:

C(s) + O₂(g) → CO₂(g) + CO

All 5 moles of C(s) reacts producing CO₂ and CO. You can write:

5 moles = CO₂ + CO (1)

And, as pressure increased by 16.4% and initial moles of oxygen are 5.00 moles. Final moles (Moles of three gases) are:

5.00moles + 5.00moles*16.4% =

5.82 moles = O₂ + CO₂ + CO (2)

Also, there are 10 moles of oxygen in the container, that is:

10 moles = O₂*2 + CO₂*2 + CO (3)

From (2) and (1), moles of O₂ are:

O₂ = 0.82 moles

Replacing in (3)

10 mol = 0.82*2 + CO₂/2 + CO

8.36 moles = CO₂*2 + CO

5 moles = CO₂ + CO

By the sum of these equations:

3.36 moles = CO₂

And

5.0 moles - 3.36 moles = CO

1.64 moles = CO

As total moles are 5.84 moles, mole fraction of the gases is:

Answer:

This question is incomplete

Explanation:

The question is incomplete because of the absence of the table but since the question says there are data from an investigation about a plant growth and five other plants (making six) of the same type, the best way to display this type of data for analyst is to use the grouped bar chart. The grouped bar chart will display the data obtained (from an investigation on plant growth) from different students on each of the six plants (of the the same type).

Colours are usually used to identify the bars (of a group) or could be used to separate the group from other groups but in this case, colours are better used to identify the bars of a group.

Answer: 9.541 kg

Explanation:

Answer:

i believe it is 0.009541

Explanation:

I know only P2O5 = Phosphorus pentoxide

Answer:

0.724 L

Explanation:

Step 1: Given data

Mass of ethanol (solute): 25.0 g

Concentration of the solution: 0.750 M

Step 2: Calculate the moles corresponding to 25.0 g of ethanol

The molar mass of ethanol is 46.07 g/mol.

25.0 g × (1 mol/46.07 g) = 0.543 mol

Step 3: Calculate the volume of the solution

We will use the following expression.

M = moles of solute / liters of solution

liters of solution = moles of solute / M

liters of solution = 0.543 mol / (0.750 mol/L)

liters of solution = 0.724 L

Answer:

Explanation:

The direct reaction of a carboxylic acid with an amine would be expected to be difficult because the basic amine would deprotonate the carboxylic acid to form a highly unreactive carboxylate.

Answer:

The correct answer is 0.6 mL.

Explanation:

We use the mathematical expression:

Ci x Vi = Cf x Vf

Where Ci is the initial concentration (5 M); Cf and Vf refers to final concentration (0.002 M) and final volume (1500 mL). With the given data, we calculate the initial volume (Vi):

Vi = (Cf x Vf)/Ci = (0.002 M x 1500 mL)/(5 M) = 0.6 mL

Therefore, we need 0.6 mL of 5 M NaCl to prepare the solution with the requested dilution.

Answer:

Three measurements that are helpful to know when working with a gas are volume, temperature, and pressure. container.

Hope this helps if its wrong correct me.

Answer:

48 minutes i think

Explanation:

Answer:

Global warming occurs a result of human activities which affects the environment negatively . It usually occurs over a long period of time. The global warming causes climate changes as a result of the ozone layer depletion.

If society took the threat of global warming seriously there will be changes in how humans handle the environment and the resources. Carbon emissions would be greatly reduced. Forest resources such as trees would also be treated specially and there would have been a reduction in mass deforestation as a result of urbanization

Given :

A certain compound contains 4.0 g of calcium and 7.1 g of chlorine.

Its relative molecular mass is 111.

To Find :

Its empirical and molecular formulas.

Solution :

Moles of calcium , [tex]n_1=\dfrac{4}{40}=0.1\ moles[/tex].

Moles of chlorine , [tex]n_2=\dfrac{7.1}{35.45}=0.2\ moles[/tex] .

The ratio calcium and chlorine is 1 : 2 .

So , the empirical formula is [tex]CaCl_2[/tex] .

Now , molecular mass of [tex]CaCl_2[/tex] is :

[tex]M=40+(2\times 35.45)\\\\M=110.9\ g[/tex]

So , [tex]n=\dfrac{111}{110.9} \approx1[/tex]

Therefore , the molecular formula is also [tex]CaCl_2[/tex] .

Hence , this is the required solution .

Answer:

Radon

Explanation:

n 1908 Ramsay and Gray, who named it niton, isolated the element and determined its density, finding it to be the heaviest known gas. It is essentially inert and occupies the last place in the zero group of gases in the Periodic Table. Since 1923, it has been called radon.

Liquid (Matter can exist in one of three main states: solid, liquid, or gas.)

Answer:

They have three to six valence electrons, so they can lose or gain electrons.

Explanation:

just took the quiz

Metalloids are metal like elements showing intermediate properties of gases and metals. They have three to six valence electrons, so they can lose or gain electrons. That's why they are conducting.

Metalloids are elements showing properties intermediate to that of metals and non-metals. They are located in the periodic table in between metals and nonmetals.

Metalloids appear as metals. They are shiny and conducting. However, their conductivity is low compared to metals and they are classified as semiconductors and they are all brittle in nature.

Boron, silicon, germanium, arsenic etc. examples of metalloids. They contains three to six valence electrons which can be delocalized or lost from the atoms.

These elements can lose electrons as well they can gain more electrons as per the bonding type. The delocalized valence electrons make them conducting. Hence option D is correct.

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Answer:

Mercury

Explanation:

This is the only metal that exists as a liquid at room temperature

Answer:

38 g as well due to the law of conservation of mass.

Explanation:

Hello,

In this case, we need to review the law of conservation of mass which states that matter cannot be neither created nor destroyed, thus, for chemical reactions, the mass of reactants at the beginning of the chemical reaction must equal the mass of products at the end in closed systems, that is why, since 38 g is the mass of reactants, the mass of the overall products is also 38 g.

Best regards.

Answer:

See attached picture.

Explanation:

Hello,

In this case, for the required carboxylic acid, we should consider a central cyclohexane that at the first carbon has a carboxyl group COOH and at the fourth carbon has two chlorine radicals as shown on the attached picture. This type of compounds need to have the carboxyl group outside the ring in order to be considered as acids, otherwise the octet rule may not be respected for a cyclic carbon.

Regards.

Answer: I did the research myself since I couldn’t find the answers.

Physical change:

Wax melting from applied heat

Grinding wheat to make flour

Adding copper with gold to make jewelry

Chemical Reaction:

Growth of a seed into a seedling

Making caramel by burning sugar

Tarnishing of silver

Explanation:

Thanks google

Answer:

Physical change:

Wax melting from applied heat

Grinding wheat to make flour

Adding copper with gold to make jewelry

Chemical Reaction:

Growth of a seed into a seedling

Making caramel by burning sugar

Tarnishing of silver

Explanation: I had to take a test.

Answer:

Very Acidic

Explanation:

I took the quiz on K12

Answer:

8.5

Explanation:

Took the test and got it correct

On an average, teenagers require 8.5 hours of sleep each night to maintain good health.

A teenager, or teen, is someone who is between 13 and 19 years of age. They are called teenagers because the number of their age contains the suffix "teen". The word "teenager" is often associated with adolescence. Most neurologists consider the brain still developing into a person's early or mid-20s. A person becomes a teenager when they become 13 years old. It ends when they turn 20 years old. Teenagers who are between 13 and 17 years old are considered both children and teenagers in most countries. Teenagers who are 18 and 19 years old may be regarded as both teenagers and adults.

The way the word is used varies. Most societies have rites of passage to mark the change from childhood to adulthood. These ceremonies may be quite elaborate.During puberty, rapid mental and physical development occurs. Adolescence is the name for this transition period from childhood to adulthood.

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Answer:

That means that the number of O2 molecules present in 2g of O2 is equal to 0.0625*NA. That's 3.76375*10^22. That is a lot of molecules. And we have not even reached the atomic level

water is watching over you

Answer:

it means the higher the water content in the air, the more moderate (less extreme) the climate is.

Answer:

Option [tex]C. \:\:0.07 \:M[/tex]  is the right choice.

Explanation:

Write down the equation and balance it.

[tex]3NaOH+H_3PO_4\Rightarrow \:Na_3PO_4+3H_2O[/tex]

For one mole of phosphoric acid, we need three moles of sodium hydroxide.

Concentration of [tex]NaOH[/tex] [tex]=Molarity=\frac{moles}{Volume}[/tex]

Mole of [tex]NaOH[/tex] [tex]= 0.2\times 50\times 10^{-3}[/tex]

[tex]=0.01\:moles[/tex]

Moles of [tex]H_3PO_4=\frac{0.01}{3}=0.0033\:moles[/tex]

Finally:

Concentration of [tex]H_3PO_4=\frac{0.0033}{0.05}=0.067\:M[/tex]

Answer:

Fireworks cause broad air contamination in a short measure of time

Explanation:

Fireworks cause broad air contamination in a short measure of time, leaving metal particles, hazardous poisons, destructive synthetic compounds and smoke noticeable all around for quite a long time. A portion of the poisons never completely decay or break down, but instead stick around in the earth, harming all they come into contact with

If the firework mixture is not pure, it is capable of causing risks to health conditions by creating hazardous explosives.

Fireworks originate from the Greek word ''pyrotechnics" which implies fire art. Fireworks is simply a missile that explodes with booms and bursts of vibrantly colorful light in a very controlled fashion.

The chemical components used in the preparation of fireworks are dependent upon the color they produce. These include:

If these mixtures are impure, it is certain that these can pose a greater risk related to health conditions by exploding abruptly. These impure gases get mixed with the air and also result in environmental hazards by mixing with the water in lakes, rivers, and streams.

In conclusion, the impurity of firework mixture has a greater effect on human health conditions.

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Answer:

1. The oxidation half-reaction is: Mn(s) ⇄ Mn²⁺(aq) + 2e⁻

2. The reduction half-reaction is: Ag⁺(aq) + 1e⁻ ⇄ Ag(s)  

Explanation:

Main reaction: 2Ag⁺(aq) + Mn(s) ⇄ 2Ag(s) + Mn²⁺(aq)

In the oxidation half reaction, the oxidation number increases:

Mn changes from 0, in the ground state to Mn²⁺.

The reduction half reaction occurs where the element decrease the oxidation number, because it is gaining electrons.

Silver changes from Ag⁺ to Ag.

1. The oxidation half-reaction is: Mn(s) ⇄ Mn²⁺(aq) + 2e⁻

2. The reduction half-reaction is: Ag⁺(aq) + 1e⁻ ⇄ Ag(s)  

To balance the hole reaction, we need to multiply by 2, the second half reaction:

Mn(s) ⇄ Mn²⁺(aq) + 2e⁻

(Ag⁺(aq) + 1e⁻ ⇄ Ag(s)) . 2

2Ag⁺(aq) + 2e⁻ ⇄ 2Ag(s)  

Now we sum, and we can cancel the electrons:

2Ag⁺(aq) + Mn(s) + 2e⁻ ⇄ 2Ag(s) + Mn²⁺(aq) + 2e⁻