I need help please ASAP

Explanation:

C4H10 + 13/2O2 ---------> 4CO2 + 5H2O

so u can work out the amount of moles by doing

moles=mass/mr

mr of C4H10 is 12 × 4 + 10 =58

=7.269/58

= 0.125moles

Then u can use the molar ratio which is

6.5:4

0.125 ÷6.5 × 4 = 0.0769moles

hope this helps:)

Answer:

Starch.

Explanation:

When the triiodide combine with starch, it forms dark blue colour. Amylose in starch is responsible for the occurrence of a deep blue color when the iodine is combine with the starch. The iodine molecule goes inside of the amylose coil which makes a linear triiodide ion complex that goes into the coil of the starch that leads to an intense blue-black color in the end so we can say that starch turns the colour into blue.

Answer:

The second and the third atomic model.

Explanation:

An element is identified by the no. of protons in the said element. Proton number cannot be changed. Both second and third atomic model have 5 protons, so they are of the same element.

Answer:

D) a four-fold increase

Explanation:

According to Gay-Lussac's law, which states that the pressure of a given amount of gas is directly proportional to the temperature at a constant volume, the pressure increases with an increase in temperature.

According to this question, at a fixed volume, a four-fold increase in the temperature of a gas will lead to a four-fold increase in the pressure as well.

Answer:

the answer is the first one

Na+

Answer:

The molar mass of Beryllium is 9.012182 u

Answer:

Az2Cy4

Explanation:

Ionic substances are composed of an ion pair. We arrive at the formula of an ionic substance by exchange of valency between the two ions involved in the compound.

In this case we have Az +4 and Cy-2. If we ignore the charges and the two ions and exchange the valency of the ions, the exchanged valencies are written as subscripts hence we arrive at the formula; Az2Cy4 as the formula of the ionic compound formed by the two ions.

Answer:

The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide.

Explanation:

Answer:

When red cabbage is treated with an acid or a base, it produces anthocyanin, a water-soluble pigment that changes color. In acidic situations with a pH less than 7, the pigment turns red, whereas in alkaline (basic) situations with a pH more than 7, the pigment turns bluish-green.

Explanation:

Answer: Volume occupied by 3.00 moles of oxygen gas under the same condition is 3.75 L.

Explanation:

Given: [tex]n_{1}[/tex] = 4.00 moles,          [tex]V_{1}[/tex] = 5.0 L

[tex]n_{2}[/tex] = 3.00 moles,                 [tex]V_{2}[/tex] = ?

Formula used is as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}[/tex]

Substitute the values into above formula as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{5.0 L}{4.00 mol} = \frac{V_{2}}{3.00 mol}\\V_{2} = 3.75 L[/tex]

Thus, we can conclude that volume occupied by 3.00 moles of oxygen gas under the same condition is 3.75 L.

Answer:

true

Explanation:

probably true

Answer:

67 L

Explanation:

Step 1: Write the balanced equation

Na₂S(aq) + 2 HCl(aq) → 2 NaCl(aq) + H₂S(g)

Step 2: Calculate the moles corresponding to 234 g of Na₂S

The molar mass of Na₂S is 78 g/mol.

234 g × 1 mol/78 g = 3.0 mol

Step 3: Calculate the moles of H₂S produced from 3.0 moles of Na₂S

The molar ratio of Na₂S to H₂S is 1:1. The moles of H₂S formed are 1/1 × 3.0 mol = 3.0 mol.

Step 4: Calculate the volume occupied by 3.0 moles of H₂S at STP

At STP, 1 mole of H₂S occupies 22.4 L.

3.0 L × 22.4 L/1 mol = 67 L

Answer:

if it is pure, the substances is either an element or a compound. if a substance is not chemically pure, it is either a heterogeneous mixture or a homogeneous mixture. if its composition is uniform throughout, it is a homogeneous.

Answer:

A little atom will leave a big hole and a big atom cant travel that fast

Explanation:

Answer:

the number of gas molecules in the sample

Answer:

53.2 mL

Explanation:

As this problem deals with the neutralization of a strong monoprotic acid and a strong base, we can solve it by using the following formula:

Where in this case:

We input the data:

And solve for Vb:

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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Answer:

D. burning wood

Explanation: It seems like the only logical answer

Tn chemical reaction, the energy is released is called as chemical energy. The burning wood releases the chemical energy. Therefore, option D is correct.

Chemical energy is the energy that is released when chemical substances engage in a chemical reaction and change into other substances. Batteries, food, and gas are a few examples of chemical energy storage mediums.

Chemical energy, such as that held in the bonds of atoms and molecules, is stored energy. As a result of a chemical process, this energy is released. A substance typically changes into an entirely different substance once its chemical energy has been released.

The body transforms the energy in meals into heat and mechanical energy. Additionally, coal's chemical energy is transformed into electrical energy in power plants. Last but not least, electrolysis is another way that the chemical energy in a battery might generate electricity.

Thus, option D is correct.

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Answer:

Enzyme ? ...............

Answer:

Q was < K. Partial pressure of hydrogen decreased, iodine increased

Explanation:

After iodine was added the Q was [Select] K so the reaction shifted toward the Products [Select] ,The partial pressure of hydrogen [Select], Iodine [Select] |,and hydrogen iodide Decreased

Based on the equilibrium:

H2(g) + I2(g) ⇄ 2HI(g)

K of equilibrium is:

K = [HI]² / [H2] [I2]

Where [] are concentrations at equilibrium

And Q is:

Q = [HI]² / [H2] [I2]

Where [] are actual concentrations of the reactants.

When the reaction is in equilibrium, K=Q.

But as [I2] is increased, Q decreases and Q was < K

The only concentration that increases is [I2], doing partial pressure of hydrogen decreased, iodine increased

Answer:

2NaCl + CuCO3

FeCl2 + BaSO4

CuCO3 + Ca(NO3)2

Explanation:

Presumably this is a double replacement reaction.

A+B + C+D → A+D + C+B

It seems I may be wrong so please try to work out the problem yourself to double check, keeping in mind the charges of each compound.

Answer:

[tex]Key=2.5x10^{-9}[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the equilibrium constant value for the reverse reaction:

[tex]2CO_2(g) \rightleftharpoons 2CO(g) + O_2(g)[/tex]

By knowing that the equilibrium expression is actually:

[tex]Key =\frac{[CO]^2[O_2]}{[CO_2]^2} =\frac{1}{Keg}[/tex]

Thus, we plug in and solve for the inverse of Keq to obtain Key as follows:

[tex]Key =\frac{1}{4.0x10^{-10}}\\\\Key=2.5x10^{-9}[/tex]

Regards!

Answer: For the equilibrium that exists in an aqueous solution of nitrous acid (HNO2, a weak acid), the equilibrium constant expression is K = [ H+] [NO2-] / [HNO2].

Explanation:

An expression that depicts the ratio of products and reactants raised to the power of their coefficients at equilibrium is called equilibrium constant.

An equilibrium constant is denoted by the symbol 'K'.

For example, the dissociation of nitrous acid in aqueous solution is as follows.

[tex]HNO_{2} \rightleftharpoons H^{+} + NO^{-}_{2}[/tex]

Hence, its expression for equilibrium constant is as follows.

[tex]K = \frac{[H^{+}][NO^{-}_{2}]}{[HNO_{2}]}[/tex]

Thus, we can conclude that for the equilibrium that exists in an aqueous solution of nitrous acid (HNO2, a weak acid), the equilibrium constant expression is K = [ H+] [NO2-] / [HNO2].

Answer:

Answer

9......

Explanation:

Explaination:

Answer:

7.4

Explanation:

Plasma proteins are part of the buffer systems of blood plasma. Plasma contains both positively and negatively charged amino and carboxyl groups. These compounds' charged portions can attract and link hydrogen(H) and hydroxyl ions(OH-), therefore act as buffers.

Plasma serves as a weak and ineffective buffer. The pH of a buffer should always be around 7.4 which is nearly neutral. As such we may deduce from the first experimental observation that there is no change in pH.

No, you absolutely need a balanced equation because you need the coefficients to figure out the molar ratios plus you need the amount of one reactant or product to determine the theoretical yield.

No, it's not possible to calculate the theoretical yield  without a balanced equation.

Theoretical yield is the yield that is calculated by the complete reaction of the limiting reagent. This is called expected or calculated amount of product.

[tex]\rm percent\; yield = \dfrac{(actual\; yield)}{(theoretical\; yield)} \times 100\\\\[/tex]

Thus, No, it's not possible to calculate the theoretical yield  without a balanced equation.

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Answer:

the relative height of M⁺ : M+1 is; 0.7418 : 0.2228

The relative heights are; In order of increasing mass 100 : 30

Explanation:

Given the data in the question;

The M⁺ peak comes from all ¹²₆C atoms

so, the probability in cholesterol, C₂₇H₄₈O is ( 98.9% )²⁷ = ( 0.989 )²⁷ = 0.7418

The M+1 peak comes from the isotopic carbon ¹³₆C.

so, the probability in cholesterol is ⇒ 1.10% × ( 98.9% )²⁶ = 0.011 × ( 0.989)²⁶

The probability for 27 carbons is ⇒  27 × 0.011 × ( 0.989)²⁶ = 0.2228

Therefore, the relative height of M⁺ : M+1 is; 0.7418 : 0.2228

The relative heights are; In order of increasing mass 100 : 30  

Answer:

a) 0.15 mol.

b) 8.95 g.

Explanation:

Hello there!

In this case, according to the given information, it is possible for us to infer this problem is solved by using the ideal gas equation:

[tex]PV=nRT[/tex]

And proceed as follows:

a) Here, we solve for the moles, n,  as follows:

[tex]n=\frac{PV}{RT} \\\\n=\frac{0.50atm*4.5L}{0.08206\frac{atm*L}{mol*K}*178K} \\\\n=0.15mol[/tex]

b) for the calculation of the mass, we recall the molar mass of butane, 58.12 g/mol, to obtain:

[tex]0.15mol*\frac{58.12g}{1mol} =8.95g[/tex]

Regards!

Answer:

1. alpha -  decreased mass by 4  - decrease atomic number by 2

2. beta electron - no change - increase by 1

3 - beta positron - no change - decrease by 1

4. gamma - no change - no change

5. electron capture - no change - decrease by 1

Explanation:

There are five main types of radioactive decay, a process where the nucleus loses energy by emitting radiation, these radiation or type of radioactive decay are alpha particles, beta particles, positron or beta positron, gamma particles and electron capture.

The effect of these particles causes a change in the number of subatomic which leads to different atomic mass and atomic numbers after the decay -

1. alpha -  decreased mass by 4  - decrease the atomic number by 2

2. beta electron - no change - increase by 1

3 - beta positron - no change - decrease by 1

4. gamma - no change - no change

5. electron capture - no change - decrease by 1