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2 years ago

HELP ME PLEASE (brainliest)

Chemistry

1 answer:

Aloiza [94]2 years ago

7 0

Answer: i would say D or the last one.

Explanation: According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants. The law of conservation of mass is useful for a number of calculations and can be used to solve for unknown masses, such the amount of gas consumed or produced during a reaction.

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A 3.82 g piece of limestone contains 2.62 g of CaCO3

Kobotan [32]

Considering the definition of percentage by mass, the mass percentage of CaCO₃ is 68.59%.

<h3>What is mass percentage</h3>

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

$mass percentage=\frac{mass of solute}{mass of solution}x100$

<h3>Mass percentage of CaCO₃</h3>

In this case, you know:

mass of CaCO₃: 2.62 grams
mass of limestone: 3.82 grams

Replacing in the definition of mass percentage:

$mass percentage=\frac{2.62 grams}{3.82 grams}x100$

<u><em>mass percentage= 68.59 %</em></u>

Finally, the mass percentage of CaCO₃ is 68.59%.

Learn more about percentage by mass:

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7 0

1 year ago

how would you write equation to show how buffers H2CO3 and NaHCO3 behave when (a) HCl is added and (b) NaOH is added.

Vlad1618 [11]

<span>H2CO3 <---> H+ + HCO3-
NaHCO3 <---> Na+ + HCO3-

When acid is added in the buffer, the excess H+ of that acid reacts with HCO3- to form H2CO3, and due to this NaHCO3 dissociates into HCO3- to attain the equilibrium. and hence there is no net effect of H+ due to pH remain almost constant. when a base is added to the buffer, the OH- ion of base react eith H+ ion present in buffer, then to attain equilibrium of H+ ion, the H2CO3 dissociates to produce H+ ion, but now there is the excess of HCO3- due to which Na+ ion react with them to attain equilibrium of HCO3-. hence there is again no net change in H+ ion due to which pH remain constant.....</span>

8 0

3 years ago

A student uses a balance to determine the mass of an object as 5.719 grams. the correct mass of the object is 5.586 grams. what

zaharov [31]

The percentage error is given by multiplying relative error by 100%.
Therefore, to get the percentage error we need relative error which is given by dividing the absolute error with the actual value.
Absolute error = 0.133
Percentage error = 0.133/5.586 × 100%
= 2.38%
The percentage error is therefore; 2.38%

8 0

2 years ago

The space race was between

Leviafan [203]

Answer:

the United States and the Soviet Union.

Explanation:

Basically we were in toe to toe with the russians for space explorations like who's gonna get to space first or moon or do such explorations

4 0

1 year ago

Describe how water molecules interact with sodium chloride molecules in order for water to dissolve salt.

Phantasy [73]

Answer:

Sodium chloride is an ionic salt that completely dissociates in water.

Explanation:

Sodium chloride in water dissociates according to the equation.

NaCl (aq) → Na + (aq) + Cl- (aq)

While water stays in balance according to the equation

2H2O (l) ⇄ H3O+(aq) + OH-(aq).

By dissociating the solute in the solvent, the water molecules pick up the sodium cations as well as the chloride anions to break the bonds in the salt crystals and thus produce the dissolution

If the ions are analyzed separately, we see that Na + interacts with water, so it would be producing sodium hydroxide, releasing protons.

If the reaction goes in the sense of products, the Na + would increase the concentration of [H +], however being a neutral salt the pH does not vary from 7, so the reaction would never go in the sense of products, but only reagents. That's why as the sodium hydroxide is a strong base, it only promotes the formation of water and the cation.

Na+ + H2O ← NaOH + H+

The same situation occurs with chloride, since no matter how much you want to form hydrochloric acid, it dissociates by promoting the formation of water plus the corresponding anion. Na + and Cl- act as too weak conjugate acid and base, so the reaction would never go in the direction of products

Cl- + H2O ← HCl + OH-

3 0

3 years ago