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harina [27]
3 years ago
6

Is mass conserved in chemical reactions? Make a prediction based on this question. Be sure to tell how you would determine wheth

er or not mass was actually conserved.
Chemistry
1 answer:
Lady_Fox [76]3 years ago
3 0

In chemical reactions mass is always conserved. we sum all of the mass before and after reaction and it should stay the same.

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Weathering of rock and sedimentation ultimately lead to the formation of___
Inga [223]
Weathering of the rock and sedimentation are decomposition processes. Through time, the minerals in the rocks soften due to pressure and heat. So, they crumble down and reduce in terms of size. Once they do, they become sand or part of the soil. So, the answer is A.
6 0
3 years ago
Read 2 more answers
At a pressure of 650 kpa 2.2L of hydrogen is used to fill a balloon to a final pressure of 115 kpa. What's the balloons volume?
Alborosie

Answer:

V₂ = 12.43 L

Explanation:

Given data:

Initial pressure = 650 KPa

Initial volume = 2.2 L

Final pressure = 115 KPa

Final volume = ?

Solution:

The given problem will be solved through the Boyles law,

"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"

Mathematical expression:

P₁V₁ = P₂V₂

P₁ = Initial pressure

V₁ = initial volume

P₂ = final pressure

V₂ = final volume  

Now we will put the values in formula,

P₁V₁ = P₂V₂

650 KPa ×2.2 L = 115 KPa × V₂

V₂ = 1430 KPa. L/ 115 KPa

V₂ = 12.43 L

4 0
3 years ago
Calcule a variação da entalpia dessa reação ( 2 NH3 (g) ---> CO(NH2)2 (s) + H2O (L) ) a partir das seguintes equações termoqu
Nitella [24]

ΔH = +438 kJ  

We have three equations:  

(I) N₂ + 3H₂ → 2NH₃; Δ<em>H</em> = -92 kJ  

(II) H₂ +½O₂ → H₂O; Δ<em>H</em> = -286 kJ  

(III) CO(NH₂)₂ + ³/₂O₂ → CO₂ + 2H₂O + N₂; Δ<em>H</em> = -632 kJ  

From these, we must devise the target equation:  

(IV) 2NH₃ + CO₂ → CO(NH₂)₂ + H₂O; Δ<em>H</em> = ?  

_________________________________

The target equation has 2NH₃ on the left, so you <em>reverse equation (I)</em>.  

When you reverse an equation, you <em>reverse the sign of its ΔH</em>.  

(V) 2NH₃ → N₂ + 3H₂; Δ<em>H</em> = +92 kJ  

Equation (V) has 1N₂ on the right, and that is not in the target equation.  

You need an equation with 1N₂ on the left.  

<em>Reverse Equation (III).</em>  

(VI) CO₂ + 2H₂O + N₂ → CO(NH₂)₂ + ³/₂O₂; Δ<em>H</em> = +632 kJ  

Equation <em>(VI)</em> has ³/₂O₂ on the right, and that is not in the target equation.  

You need ³/₂O₂ on the left.  

Multiply <em>Equation (II) by three</em>.  

When you multiply an equation by three, you <em>multiply its ΔH by thre</em>e.

(VII) 3H₂ +³/₂O₂ → 3H₂O; Δ<em>H</em> = -286 kJ  

Now, you add equations (V), (VI), and (VII), <em>cancelling species</em> that appear on opposite sides of the reaction arrows.  

When you add equations, you add their Δ<em>H</em> values.  

_______________________________________

We get the target equation (IV):  

(V) 2NH₃ → <u>N</u>₂ + <u>3H</u>₂;                                    ΔH = +  92 kJ  

(VI) CO₂ + <u>2H</u>₂<u>O</u> + <u>N</u>₂ → CO(NH₂)₂ + ³/₂<u>O</u>₂; ΔH = +632 kJ  

(VII) <u>3H</u>₂ +³/₂<u>O</u>₂ → <u>3</u>H₂O;                             ΔH =   -286 kJ

(IV) 2NH₃ + CO₂ → CO(NH₂)₂ + H₂O;          ΔH =  +438 kJ  


7 0
3 years ago
4 physical properties of spoonfull of sugar
almond37 [142]
Small crystals 
<span>white, brown </span>
<span>hard as in solid at room temp </span>
<span>sweet </span>
3 0
3 years ago
Read 2 more answers
Best answer and explanation will get marked brainiest
Darina [25.2K]

The number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.

<h3>What is significant figures?</h3>

Significant figures of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something.

Also significant figures can be defined as, the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.

Examples of significant figures;

  • 405 = 3 significant figures
  • 405000 = 3 significant
  • 0.040500 = 5 significant figures

<u>Note:</u> leading zeros are not significant but trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point.

345,000 = 3.45 x 10⁵ (3 significant figures)

Thus, the number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.

Learn more about significant figures here: brainly.com/question/24491627

#SPJ1

4 0
2 years ago
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