what is this for questions 2

Explanation:

The mole (abbreviated mol) is the SI measure of quantity of a “chemical entity,” such as atoms, electrons, or protons. It is defined as the amount of a substance that contains as many particles as there are atoms in 12 grams of pure carbon-12.

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Answer:

B.

Explanation:

Answer:

B is the correct answer

Explanation:

Answer:d

Explanation:

Answer:

See answer below

Explanation:

a.) Lithium Chloride, LiCl is soluble in water.

b.) Silver Chloride, AgCl is insoluble in water.

c.) Barium Carbonate, BaCO3 is insoluble in water.

d.)Potassium, K2 is soluble in water.

e.) Iron (III) Nitrate Fe(NO3)3 is soluble in water.

Answer:the first one is D second one is A and the third one is A   :D

Explanation:

Answer:

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According to the concept of Avogadro's number, there are 29.056×10²³ molecules in 77.2 g of methane.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number

In the given example, number of moles=77.2/16=4.825 moles

If 1 mole has 6.023×10²³ molecules , then 4.825 moles will have 4.825×6.023×10²³ /1=29.056×10²³ molecules .

Thus, there are 29.056×10²³ molecules in 77.2 g of methane.

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Answer: 1075.5 mph

Explanation:anything moving at 4.78*10^4 cm/sec

equivalent to

cm —> miles = 1/1.6*10^5

sec —> hr = 1/3600

[4.78*10^4]*3600/1.6*10^5 = 1075.5 mph

Explanation:

Moreover, increasing use of fossil fuels also causes serious environmental problems. Hence, there is a pressing need to use renewable energy sources like solar energy, wind, tide, biomass and energy from waste material. (i) it reduces the dependence on fossil fuels for energy. (ii) they donot produces pollution.

Answer:A) After the values are added, we determine how many significant figures are involved by looking at the decimal places of the original values. 52.13 had only 2 digits past the decimal point so the answer can only contain 2 significant numbers after the decimal point which would be 53.88 g

Explanation:

Answer:

1105.29 grams

Explanation:

If you calculate the molar mass of Ca3(PO4)4 you'll get 500.13. Molar mass is the mass of one mole of a substance. Multiply 500.1194 by 2.21 because we have 2.21 moles to get 1105.264 grams.

The molar mass of Ca is 40.078 grams, and there are 3 of them. So 40.078 x 3 is 120.234 grams.

The molar mass of P is 30.974 and there are 4 P's, so 30.974 x 4 is 123.896 grams.

The molar mass of O is 16 grams and there are 6 of them. Again, 16 x 16 is 256 grams.

Add up 120.234 + 123.896 + 256 to get the molar mass of Ca3(PO4)4, 500.13.

Answer:

Explanation:

Divide the mass by the density and the units of grams will cancel so youll end up with mL.

(52.757g)/(12.5g/mL) = 4.2mL

In condensation, matter changes from a gas to a liquid. All matter is made of tiny moving particles called molecules. Evaporation and condensation happen when these molecules gain or lose energy. This energy exists in the form of heat.

Answer:

90 drops

Explanation:

1 teaspoon = 60 drops

Half a teaspoon = 60 ÷ 2 = 30 drops

1 and a half = 60 + 30 = 90

Answer: The student observed only one liquid phase because The student removed the aqueous layer instead of the organic layer and then added organic solvent to more organic layer. Diethyl ether is less dense than water.

Explanation:

In organic chemistry, which is the chemistry of carbon atoms, liquid-liquid extraction techniques are used to separate solutes from its crude reaction mixtures. An example of liquid- liquid extraction technique used is the Separatory funnel.

The Separatory funnel extraction technique allows the separation of solutes based on their solubilities in two immiscible liquids. This appears as two phases or layers with the organic solvent on top while the aqueous solution is below the funnel. This is because the organic solvents are less dense than the aqueous solution.

From the question, the student had a dissolved organic compound in an aqueous solution and was given an organic solvent, diethyl ether for its extraction. When the first 10ml of ether was added, the dissolved organic compound mixed with it and remained in the top layer of the mixture. The student removes the lower layer after the first extraction and adds the second 10mL portion of ether to the upper layer remaining in the separatory funnel. After shaking the funnel, the student observes only one liquid phase with no interface because more organic solvent was added to the organic layer that remained after the aqueous layer was removed.

Answer:

a. the width of region 2 would be smaller

If the same reaction was shown without a catalyst, the height of region 2 would be larger, so the correct option is (C).

A catalyst is a substance that speeds up the rate of a chemical reaction without being consumed in the process. It works by providing an alternate pathway for the reaction with a lower activation energy, making it easier for the reactants to transform into products.

Catalysts can be solids, liquids, or gases, and they can be homogeneous or heterogeneous, depending on whether they are in the same phase as the reactants or in a different phase.

Catalysts are widely used in many industrial processes, such as the production of fertilizers, plastics, and fuels, to increase the efficiency and reduce the cost of the reaction. They can also be found in biological systems, where they play a crucial role in metabolic processes, such as the breakdown of food in the digestive system or the conversion of light into chemical energy in photosynthesis.

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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:

The balanced molecular equation for the reaction is:

[tex]2HNO_{3_{(aq)} }[/tex] + [tex]K_{2} CO_{3} _{(s)}[/tex] → [tex]2KNO_{3} _{(s)}[/tex] + [tex]H_{2} O_{(l)[/tex] + [tex]CO_{2} _{(g)}[/tex]↑

Explanation:

The weak nitric acid reacts with the strong potassium base to produce salt, water and carbon dioxide which is given off.

Molecular ratio of reactants is 2 : 1.

All phases are represented in the equation: aq for aqueous, l for liquid and g for gas (notice how they are written in subscript).

I hope this was helpful.

Answer:

8 × 10³ mol N₂

Explanation:

Step 1: Write the balanced equation

2 C₃H₅N₃O₉ ⇒ 6 CO₂ + 5 H₂O + 0.5 O₂ + 3 N₂

Step 2: Convert the mass of C₃H₅N₃O₉ from tons to grams

We will use the conversion factor 1 t = 907185 g.

1.320 t × 907185 g/1 t = 1.197 × 10⁶ g

Step 3: Calculate the moles corresponding to 1.197 × 10⁶ g of C₃H₅N₃O₉

The molar mass of C₃H₅N₃O₉ is 227 g/mol.

1.197 × 10⁶ g × 1 mol/227 g = 5.27 × 10³ mol

Step 4: Calculate the moles of N₂ formed from 5.27 × 10³ moles of C₃H₅N₃O₉

The molar ratio of C₃H₅N₃O₉ to N₂ is 2:3.

5.27 × 10³ mol C₃H₅N₃O₉ × 3 mol N₂/2 mol C₃H₅N₃O₉ = 7.91 × 10³ mol N₂ ≈ 8 × 10³ mol N₂

Answer:

Easy, the flame is smaller but burns hotter.

Explanation:

Answer: The components are Strontium (Sr) and Phosphorous (P). The symbol for the element that forms the positive cation is [tex]Sr^{2+}[/tex]. The symbol for the element that forms the negative anion is [tex]P^{3-}[/tex]. The subscript on the cation in the neutral formula is 3 and the subscript on the anion in the neutral formula is 2.

Explanation:

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.

Here in strontium phosphide , element strontium is having an oxidation state of +2 called as [tex]Sr^{2+}[/tex] cation and element phosphorous [tex]P^{3-}[/tex] is an anion with oxidation state of -3. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral strontium phosphide [tex]Sr_3P_2[/tex]

Answer:

The mouth uses both mechanical and chemical digestion. Mechanical digestion involves physically breaking down the food into smaller pieces (using the jaw/teeth). However, chemical digestion then takes over and starts breaking down the food into simpler nutrients that can be used by the cells using saliva, which is naturally made within the mouth.

Hope this helps you! Have a great day! :D

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A cooling curve has two flat lines, or plateaus. The plateau at the higher temperature represents condensation of a gas and the correct option is option C.

When a solid substance is heated until it is completely melted, and then heated further and allowed to cool slowly, the curve obtained by plotting temperature against time is known as the cooling curve.

The gradient of the cooling curve is related to the heat capacity, the thermal conductivity of the substance, and the external temperature. The more heat is required to change the temperature of the substance, the slower it cools, so the smaller the gradient of the curve. The higher the thermal conductivity, the faster heat is transferred, so the faster the substance cools.

Therefore, A cooling curve has two flat lines, or plateaus. The plateau at the higher temperature represents condensation of a gas and the correct option is option C.

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