*2Al(OH), + 3H,SO, Al(SO4)2 + 6H2O<br> reaction type

Which of the following is an example of a physical change in matter?

sineoko [7]

Answer is B.

Explanation:

A physical change is one in which there is no change in chemical composition of a substance. while a process in which there is change in chemical composition it is called a chemical change.

5 0

3 years ago

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A 100 gram glass container contains 200 grams of water and 50.0 grams of ice all at 0°c. a 200 gram piece of lead at 100°c is ad

ASHA 777 [7]

$0 \; \textdegree{\text{C}}$

Explanation:

Assuming that the final (equilibrium) temperature of the system is above the melting point of ice, such that all ice in the container melts in this process thus

$E(\text{fusion}) = m(\text{ice}) \cdot L_{f}(\text{water}) = 66.74 \; \text{kJ}$ and
$m(\text{water, final}) = m(\text{water, initial}) + m(\text{ice, initial}) = 0.250 \; \text{kg}$

Let the final temperature of the system be $t \; \textdegree{\text{C}}$ . Thus $\Delta T (\text{water}) = \Delta T (\text{beaker}) = t(\text{initial}) - t_{0} = t \; \textdegree{\text{C}}$

$Q(\text{water}) &= &c(\text{water}) \cdot m(\text{water, final}) \cdot \Delta T (\text{water})= 1.047 \cdot t\; \text{kJ}$ (converted to kilojoules)
$Q(\text{container}) &= &c(\text{glass}) \cdot m(\text{container}) \cdot \Delta T (\text{container})= 0.0837 \cdot t \; \text{kJ}$
$Q(\text{lead}) &= &c(\text{lead}) \cdot m(\text{lead}) \cdot \Delta T (\text{lead})= 0.0255 \cdot (100 - t)\; \text{kJ}$

The fact that energy within this system (assuming proper insulation) conserves allows for the construction of an equation about variable $t$ .

$E(\text{absorbed} ) = E(\text{released})$

$E(\text{absorbed} ) = E(\text{fushion}) + Q(\text{water}) + Q(\text{container})$
$E(\text{released}) = Q(\text{lead})$

Confirm the uniformity of units, equate the two expressions and solve for $t$ :

$66.74 + 1.047 \cdot t + 0.0837 \cdot t = 0.0255 \cdot (80 - t)$

$t \approx -55.95\; \textdegree{\text{C}} < 0\; \textdegree{\text{C}}$ which goes against the initial assumption. Implying that the final temperature does <em>not</em> go above the melting point of water- i.e., $t \le 0 \; \textdegree{\text{C}}$ . However, there's no way for the temperature of the system to go below $0 \; \textdegree{\text{C}}$ ; doing so would require the removal of heat from the system which isn't possible under the given circumstance; the ice-water mixture experiences an addition of heat as the hot block of lead was added to the system.

The temperature of the system therefore remains at $0 \; \textdegree{\text{C}}$ ; the only macroscopic change in this process is expected to be observed as a slight variation in the ratio between the mass of liquid water and that of the ice in this system.

3 0

3 years ago

9

marishachu [46]

Answer:

B. as a food preservative in the manufacture of detergents

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8 0

3 years ago

Why does water evaperate

Juli2301 [7.4K]

Explanation:

water evaporates because when h2o (water) particles heat up, they gain energy causing them to start to vibrate. this moves the oarticles further and further away from eachother and making the substance less dense, and turning it into a gas. meaning it has evaporated

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2 years ago

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An organic (covalent) compound is determined to contain 25.54% carbon, 6.43% hydrogen, and 68.03% oxygen. The molar mass of this

aliina [53]

Answer:

https://courses.lumenlearning.com/sanjacinto-atdcoursereview-chemistry1-1/chapter/formula-mass-and-the-mole-concept/

Explanation:

https://courses.lumenlearning.com/sanjacinto-atdcoursereview-chemistry1-1/chapter/formula-mass-and-the-mole-concept/

the answer should be in there

6 0

3 years ago

*2Al(OH), + 3H,SO, Al(SO4)2 + 6H2O reaction type