please answer this chemistry question​

Answer:

Total number of gum drops = 10 + 17 +18

= 45

Explanation:

[tex] \frac{10}{45} \times 100 \\ = 22.222222\ \ \% \\ 22\% \: gum \: drops \: \\ to \: 2 \: sf[/tex]

Answer:

[tex]pH=9.32[/tex]

Explanation:

Hello there!

In this case, according to the given scenario, it turns out necessary for us to realize that the addition of NaOH consumes the conjugate base, NH4Cl, and produces more base, NH3; that is why the reaction taking place is:

[tex]NH_4^++OH^-\rightarrow NH_3+H_2O[/tex]

Thus, the reacting moles of ammonium and hydroxide ions are:

[tex]n_{NH_4^+}=0.0800L*0.188mol/L=0.01504mol\\\\n_{OH^-}=0.0200L*0.100mol/L=0.00200mol[/tex]

Thus, the resulting moles of ammonium and ammonia are respectively:

[tex]n_{NH_4^+}=0.01504mol-0.00200mol=0.01304mol\\\\n_{OH^-}=0.0800L*0.163mol/L+0.00200mol=0.01504mol[/tex]

Then, by using the Henderson-Hasselbach equation and recalling the pKb of ammonia (4.74), we first calculate the pOH as follows:

[tex]pOH=pKb+log(\frac{n_{NH_4^+}}{n_{NH_3}} )\\\\pOH=4.74+log(\frac{0.01304mol}{0.01504mol} )\\\\pOH=4.68[/tex]

And finally the pH:

[tex]pH=14-4.68\\\\pH=9.32[/tex]

Regards!

Answer:

D. length × width

Explanation:

eg. 30 cm(length) × 20cm(width) = 600cm²

Answer:

The three freezing points will all be slightly different. It is given that a water solution has a freezing point of zero degrees Celsius, so water would have a freezing temperature below that. Salt will lower the freezing point, the more that is added.

Explanation:

[tex]CuCl_2+2NaNO_3 \rightarrow Cu(NO_3)_2 + 2NaCl[/tex]

Answer:

[tex]Y_A=92.1\%\\\\Y_B=89.6\%[/tex]

Explanation:

Hello there!

In this case, according to the given chemical equation for the reaction for the production of potassium permanganate, we can see a 2:2 mole ratio of this product to the starting manganese (II) oxide, which means, we can calculate the theoretical yield of the former via stoichiometry:

[tex]m_{KMnO_4}=50.0gMnO_2*\frac{1molMnO_2}{86.94gMnO_2}*\frac{2molKMnO_4}{2molMnO_2} *\frac{158.034gKMnO_4}{1molKMnO_4} \\\\m_{KMnO_4}=90.9gKMnO_4[/tex]

Now, we are able to compute the percent yields, by using the actual yield each scientist got:

[tex]Y_A=\frac{83.67g}{90.9g} *100\%=92.1\%\\\\Y_B=\frac{81.35g}{90.9g} *100\%=89.6\%[/tex]

Regards!

[tex]P_{1} = \text{2.50 atm}[/tex]

[tex]T_{1} = 15^{\circ}\text{C + 273 = 288 K}[/tex]

[tex]V_{1} = \text{4.5 L}[/tex]

[tex]P_{2} = \text{0.85 atm}[/tex]

[tex]V_{2} = \text{2.5 L}[/tex]

[tex]T_{2}[/tex]

[tex]\dfrac{P_{1}V_{1}}{T_{1}} = \dfrac{P_{2}V_{2}}{T_{2}}[/tex]

[tex]T_{2} = T_{1} \times \dfrac{P_{2}}{P_{1}} \times \dfrac{V_{2}}{V_{1}}[/tex]

[tex]T_{2} = \text{288 K} \times \dfrac{\text{0.85 atm}}{\text{2.50 atm}} \times \dfrac{\text{2.5 L}}{\text{4.5 L}}[/tex]

[tex]\boxed{T_{2} = \text{54.4 K}}[/tex]

[tex]\\[/tex]

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Answer:

42000km

Explanation:

Average Speed (v) can be calculated using the formula as follows:

Average speed = distance (d) ÷ time (t)

According to this question, a space shuttle travels around the Earth at a constant speed of 28000 km/hr in 90 minutes.

Since 60 minutes = 1 hr

90 minutes = 90/60

= 3/2 or 1.5hours.

Using speed = distance/time

Distance (km) = speed × time

Distance = 28000 km/hr × 1.5hr

Distance = 42000km

Answer:

true

Explanation:

because an organism have many roles in food web

The molality of a solution that has 4 mol of KCI in 0.800 kg of water is  4 mol/ 0.800 kg.

Therefore option B is correct.

b is  described as a measure of the number of moles of solute in a solution corresponding to 1 kg or 1000 g of solvent.

In order to  calculate molality, we  need to divide the number of moles of solute by the mass of the solvent in kilograms.

Molality = Number of moles of solute / Mass of solvent in kilograms

Molality = 4 mol / 0.800 kg

In conclusion, the molality is  described as a measure of the concentration of a solution expressed in terms of the number of moles of solute per kilogram of solvent.

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Detritivore

Explanation:

they eat the dead things

Answer:

The given electronic configuration is long hand notation.

Explanation:

Long-hand notation of representing electronic configuration is defined as the arrangement of total number of electrons that are present in an element.

Noble-gas notation of representing electronic configuration is defined as the arrangement of valence electrons in the element. The core electrons are represented as the previous noble gas of the element that is considered.

The given electronic configuration of potassium (K):  

The above configuration has all the electrons that are contained in the nucleus of an element. Thus, this configuration is a long-hand notation.

Answer:

A

Explanation:

Answer:

12.6

Explanation:

[tex]no \: of \: mole= \frac{mass}{molar \: mass} [/tex]

0.7=mass/(2+16)

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 12.6g  is the mass in grams of 0.700 moles of water.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number. The stoichiometry represents the number of moles.

Mathematically,

number of moles of water=given mass of water÷ molar mass of water

Molar mass of 1 mole of water= 18 g/mol

mass of water= ?

0.700 moles=moles of water

Substituting all the given values in the above equation, we get

0.700 moles=mass of water ÷ 18 g/mol

mass of water  =12.6g

Therefore, 12.6g  is the mass in grams of 0.700 moles of water.

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Explanation:

First you must calculate the number of moles in this solution, by rearranging the equation. No. Moles (mol) = Molarity (M) x Volume (L) = 0.5 x 2. = 1 mol.

For NaCl, the molar mass is 58.44 g/mol. Now we can use the rearranged equation. Mass (g) = No. Moles (mol) x Molar Mass (g/mol) = 1 x 58.44. = 58.44 g.

Answer:

Number of moles : Mass (g) ÷ relative atomic mass

Answer:

pH = 11.3

Explanation:

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

Concentration of hydronium ion [H₃O⁺] = 4.950×10¯¹² M

pH =.?

The pH of a solution is defined by the following equation:

pH = –Log [H₃O⁺]

Thus, with the above formula, we can obtain the pH of the solution as follow:

Concentration of hydronium ion [H₃O⁺] = 4.950×10¯¹² M

pH =.?

pH = –Log [H₃O⁺]

pH = –Log 4.950×10¯¹²

pH = 11.3

Answer:

(a): The theoretical yield of silicon is 72.33 kg.

(b): The percent yield of the reaction is 91.25 %.

Explanation:

Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.

Excess reagent is defined as the reagent which is left behind after the completion of the reaction.

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]       .....(1)

For [tex]SiO_2[/tex]:

Given mass = 155.0 kg = 155000 g          (Conversion factor: 1 kg = 1000 g)

Molar mass = 60 g/mol

Putting values in equation 1:

[tex]\text{Moles of }SiO_2=\frac{155000g}{60g/mol}=2583.3mol[/tex]

For carbon:

Given mass = 78.2 kg = 78200 g

Molar mass = 12 g/mol

Putting values in equation 1:

[tex]\text{Moles of carbon}=\frac{78200g}{12g/mol}=6516.67mol[/tex]

The chemical equation for the reaction of silicon dioxide and carbon follows:

[tex]SiO_2+2C\rightarrow Si+2CO[/tex]

By stoichiometry of the reaction:

1 mole of [tex]SiO_2[/tex] reacts with 2 moles of carbon

So, 2583.3 moles of [tex]SiO_2[/tex] will react with = [tex]\frac{2}{1}\times 2583.3=5166.4mol[/tex] of carbon

As the given amount of carbon is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, [tex]SiO_2[/tex] is considered a limiting reagent because it limits the formation of the product.

By stoichiometry of the reaction:

1 mole of [tex]SiO_2[/tex] produces 1 mole of silicon

So, 2583.3 moles of [tex]SiO_2[/tex] will produce = [tex]\frac{1}{1}\times 2583.3=2583.3mol[/tex] of silicon

Since the molar mass of silicon = 28 g/mol

Putting values in equation 1:

[tex]\text{Mass of Si}=2583.3mol\times 28g/mol=72332.4g=72.33 kg[/tex]

Hence, the theoretical yield of silicon is 72.33 kg.

The percent yield of a reaction is calculated by using an equation:

[tex]\% \text{yield}=\frac{\text{Measured value}}{\text{Theoretical value}}\times 100[/tex]              ......(2)

Given values:

Measured value of silicon = 66.0 kg

Theoretical value of silicon  = 72.33 kg

Putting values in equation 1:

[tex]\% \text{yield}=\frac{66.0kg}{72.33kg}\times 100\\\\\% \text{yield}=91.25 \%[/tex]

Hence, the percent yield of the reaction is 91.25 %.

Answer: The factor that lead to cyclopropane being less stable than the other cycloalkanes is the presence of a RING STRAIN.

Explanation:

In organic chemistry, the end carbon atoms of an open aliphatic chain can join together to form a closed system or ring to form cycloalkanes. Such compounds are known as cyclic compounds. Examples include cyclopropane, cyclobutane, cyclopentane and many among others.

Cyclopropane is less stable than other cycloalkanes mentioned above because of the presence of ring strain in its structural arrangement. The ring strain is the spatial orientation of atoms of the cycloalkane compounds which tend to give off a very high and non favourable energy. The release of heat energy which is stored in the bonds and molecules cause the ring to be UNSTABLE and REACTIVE.

The presence of the ring strain affects mainly the structures and the conformational function of the smaller cycloalkanes. cyclopropane, which is the smallest cycloalkane than the rest mentioned above, contains only 3 carbons with a small ring.

Answer:

The solid-liquid line in the water phase diagram has a negative slope, whereas for most other substances it has a positive slope.

The ice has a lower density as compared to water still they have in the solid phase.

In the solid-liquid line in the water phase diagram it contains the negative slope. While the most other substance should have the positive slope.

Also, when the pressure is applied so the higher density should be favored. In the water, the highest density phase should be likely the liquid water.

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Answer:

A mixture of sulfuric acid and nitric acid will produce small quantities of the nitronium ion (NO2 ): The nitronium ion has a central nitrogen atom with a positive charge double bonded to two oxygen atoms on both sides. Each oxygen atom carries two lone pairs of electrons. Does the nitronium ion have any significant resonance structures?

Explanation:

The structure of nitronium ion is shown below:

Any molecule to exhibit resonance, it should have alternating double bonds.

Resonance is the phenomenon in which the structure of a molecule can be represented in two or more forms and each form is called canonical form.

The canonical forms do not differ in the position of atoms and they differ only in the position of double bonds.

For the given molecule, there are no alternating double bonds.

Hence, nitronium ion does not exhibit any significant resonance structures.

For exothermic reactions, ΔH is always negative, energy is considered a product, and energy is released in the reaction.

An exothermic reaction is one in which energy, usually in the form of heat, is released to the environment from the reaction. In other words, the final temperature of an exothermic reaction would always be more than the initial temperature.

This also means that heat energy is a product of exothermic reactions and this heat is released to the environment from the reaction.

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Answer:

a, d, and e is correct on edge of the nuity

Explanation:

have a good day

Answer:

the answer is the first one

Na+

Explanation:

Energy is essential to life and all living organisms. The sun, directly or indirectly, is the source of all the energy available on Earth. Our energy choices and decisions impact Earth's natural systems in ways we may not be aware of, so it is essential that we choose our energy sources carefully

Answer:

49.5J/°C

Explanation:

The hot water lost some energy that is gained for cold water and the calorimeter.

The equation is:

Q(Hot water) = Q(Cold water) + Q(Calorimeter)

Where:

Q(Hot water) = S*m*ΔT = 4.184J/g°C*54.56g*(80.4°C-59.4°C) = 4794J

Q(Cold water) = S*m*ΔT = 4.184J/g°C*47.24g*(59.4°C-40°C) = 3834J

That means the heat gained by the calorimeter is

Q(Calorimeter) = 4794J - 3834J = 960J

The calorimeter constant is the heat gained per °C. The change in temperature of the calorimeter is:

59.4°C-40°C = 19.4°C

And calorimeter constant is:

960J/19.4°C =

Answer:

Actually the answer is B Malleability, conductivity

Explanation:

Answer:

I think the answer is A

Explanation:

the temperature of solids , liquids and gases can be easily measured

Answer:

See explanation and image attached

Explanation:

A Grignard reagent is an alkyl magnesium halide. If it reacts with ethyl formate, an intermediate is formed as shown.

This intermediate can undergo water hydrolysis to form a diol, ethanol and MgBrOH.

Oxidation of the diol obtained now yields the corresponding alkanal which in this case is ethanal.

The scheme of the reaction is shown in the image attached to this answer.

Answer:

Methanol and butanol are alcohols. Alcohols have the same_______________ as alkanes and the __________ identifies the compound as an alcohol.

Explanation:

Alcohols belong to a group of organic compounds which contain -OH group as the functional group.

So alcohols have the same carbon -hydrogen bonds as alkanes and the        -OH functional group identifies the compound as an alcohol.