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2 years ago

Question 21 of 25 Which of the following requires a chemical change?

Chemistry

2 answers:

Vesna [10]2 years ago

3 0

Answer:

c . Letting the fizz escape from a soda

lilavasa [31]2 years ago

3 0

Answer: a

because there is a fire, it is a chemical change causing the marshmallow to melt.

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Please help!!

antiseptic1488 [7]

Answer:

Explanation:

Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena.[1] The term law has diverse usage in many cases (approximate, accurate, broad, or narrow) across all fields of natural science (physics, chemistry, astronomy, geoscience, biology). Laws are developed from data and can be further developed through mathematics; in all cases they are directly or indirectly based on empirical evidence. It is generally understood that they implicitly reflect, though they do not explicitly assert, causal relationships fundamental to reality, and are discovered rather than invented.[2]

4 0

4 years ago

The boiling point of bromine is 59 °C. Which of the following best predicts the boiling point of iodine monochloride, a polar co

soldier1979 [14.2K]

Answer:

Higher than 59 °C because dipole-dipole interactions in iodine monochloride are stronger than dispersion forces in bromine.

Explanation:

I just took the test and i got it right

6 0

4 years ago

Read 2 more answers

Given 3.4 grams of x compound with a molar mass of 85 g and 4.2 grams of y compound with a molar mass of 48 g How much of compou

Ulleksa [173]

Answer:

$4.36~g~XY$

Explanation:

In this case, we can start with the reaction:

$2X + Y_2~->~2XY$

If we check the reaction, we will have 2 X and Y atoms on both sides. So, the reaction is balanced. Now, the problem give to us two amounts of reagents. Therefore, we have to find the limiting reagent. The first step then is to find the moles of each compound using the molar mass:

$3.4~g~X\frac{1~mol~X}{85~g~X}=0.04~mol~X$

$4.2~g~Y_2\frac{1~mol~Y_2}{48~g~Y_2}=0.0875~mol~Y_2$

Now, we can divide by the coefficient of each compound (given by the balanced reaction):

$\frac{0.04~mol~X}{1}=~0.04$

$\frac{0.0875~mol~Y_2}{2}=0.04375$

The smallest value is for "X", therefore this is our limiting reagent. Now, if we use the molar ratio between "X" and "XY" we can calculate the moles of XY, so:

$0.04~mol~X\frac{2~mol~XY}{2~mol~X}=0.04~mol~XY$

Finally, with the molar mass of "XY" we can calculate the grams. Now, we know that 1 mol X = 85 g X and 1 mol $Y_2$ = 48 g $Y_2$ (therefore 1 mol Y = 24 g Y). With this in mind the molar mass of XY would be 85+24 = 109 g/mol. With this in mind:

$0.04~mol~XY\frac{109~g~XY}{1~mol~XY}=4.36~g~XY$

I hope it helps!

6 0

4 years ago

Create a food chain that shows the energy transfer from the sun to a grizzly bear. Include four transitions (arrows) in your foo

lidiya [134]

Sun⇒ Phytoplankton (Producer)⇒ Zooplankton (Primary consumer)⇒ Fish (Secondary consumer)⇒ Bear (Tertiary consumer).

A food chain is a sequence of transfer of food and energy when one organism is consumed by another organism.
A food chain is always unidirectional sequence.
In the provided food chain the sun is the source of energy required for the preparation of food by the phytoplankton that is an aquatic autotroph which will prepare its food by the process of photosynthesis.
The phytoplankton being producer of biomass is consumed by the zooplankton that is the primary consumer than the zooplankton will be consumed by the fish that is the secondary consumer and carnivore by origin and finally the fish will be consumed by the bear that is also carnivore and is tertiary consumer.