Obi is trying to determine if a powdery, solid substance is an element or a compound. After recording some observations, he strongly heats a sample of the solid over a burner flame. After fifteen minutes, he turns off the flame and allows the sample to cool. He records his final observations in the data table.
Which is the best explanation of his results?
The heating changed some of the sample to gas, causing the mass to decrease without breaking down the sample. Therefore, the original sample is a compound.
The appearance stayed the same, showing that the sample was not broken down by heating. Therefore, the original substance is an element.
The mass decreased during heating and some of the impurities escaped. Therefore, the original substance is an element.
The chemical reaction with acid changed, showing that the sample was broken down by heating. Therefore, the original substance is a compound
Answers
Answer: I am thinking C maybe.
Explanation: I don't if this is right but I think it is C.
Answer:
D
Explanation:
Took the test on edge...
Related Questions
Is the equation C2H4 —> 2C + 2H2 + 52.3 exothermic or endothermic?
Answers
Answer:
Exothermic
Explanation:
Please help me with this question after I have help with my questions i will be giving away 50 points to 4 people to keep on the look out on my page xxx
Answers
Answer:
I swear I would help if I knew what the hell was going on on that picture XD
Answer:
D
Explanation:
factors like heat on mcls work on a bell curve, meaning they peak and go down
Which of the following has the smallest radius?
A. Br-
B. Br
C. I-
D. I
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B) Br
..................
The equation, reactants
product + thermal energy, describes a(n)_____
reaction.
Answers
Answer: Here you go
Explanation:
The general equation for an exothermic reaction is: Reactants → Products + Energy.
Given the standard heats of reaction
Reaction ∆H 0
M(s) + 2 X2(g) → MX4(g) −98.7 kJ/mol
X2(g) → 2 X(g) +327.3 kJ/mol
M(g) → M(s) −20.1 kJ/mol
calculate the average bond energy for a single
M-X bond.
Answer in units of kJ/mol.
Answers
Answer:
Explanation:
M(s) → M (g ) + 20.1 kJ --- ( 1 )
X₂ ( g ) → 2X (g ) + 327.3 kJ ---- ( 2 )
M( s) + 2 X₂(g) → M X₄ (g ) - 98.7 kJ ----- ( 3 )
( 3 ) - 2 x ( 2 ) - ( 1 )
M( s) + 2 X₂(g) - 2 X₂ ( g ) - M(s) → M X₄ (g ) - 98.7 kJ - 2 [ 2X (g ) + 327.3 kJ ] - M (g ) - 20.1 kJ
0 = M X₄ (g ) - 4 X (g ) - M (g ) - 773.4 kJ
4 X (g ) + M (g ) = M X₄ (g ) - 773.4kJ
heat of formation of M X₄ (g ) is - 773.4 kJ
Bond energy of one M - X bond = 773.4 / 4 = 193.4 kJ / mole
Heat rising in a hot-air balloon is an example of __________. conduction convection radiation solar
Answers
Answer:Condensation
Explanation:
it
Answer:
convection
Explanation:
I took test I got 100%
Where does the heat that is needed to warm the surface of the ocean come from? A. the Sun B. the Earth's interior C. animals D. the Earth's surface
Answers
Answer:
A. The Sun
Explanation:
Answer:
A
Explanation:
Most of our heat source on Earth comes from the Sun.
Is sulfur dioxide a element?
Answers
yes it is a element.
All 6 sides of a cube measure 65mm. Calculate the volume of the cube in cm32
Answers
What is a scale and why do you use it?
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Answer:
Scale is defined as a system or series of marks used for measuring or registering. An example of scale is what someone would use to figure out the length of something. An example of scale is what someone would use to find out how much they weigh.
Explanation:
A train travels at an average speed of 25 miles per hour. How long does it take the train to travel 2000 miles?
Answers
nevermind. I was wrong. I didn't see the other answers
A black hole is a
a. an object of zero volume and infinite density
b. an object from which nothing, not even light, can escape
c. an object that emits x rays as matter falls into it
d. an object that disappears from our universe
e. all of the above
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Answer:
B. an object from which nothing, not even light, can escape
Explanation:
what are 2 physical changes in the carbon cycle?
Answers
Answer:
Today, the carbon cycle is changing. humans are moving more carbon into the atmosphere from other part of the earth system. more carbon is moving to the atmosphere where fossil fuels, like coal and oil, are burned.more carbon is moving to the atmosphere as you may get rid of forest by burning the tree
Explanation:
hope this give you a hint
How is iodine 131 similar to a normal atom of iodine?
Answers
Answer: Iodine 131 is a radioisotope with a very short half-life of 8.02 days, making it highly radioactive.
Explanation:
Flowering plants are the most successful group of land plants. This is due, in part, to the trait that could be the label for point C. in the cladogram. Consider the organization of the cladogram. What trait, besides flowers, is unique to this group of plants?
Answers
Answer:
seeds are protected in fruits in such kind of plants.
Explanation:
The flowering plants are also known as Angiospermae, or Magnoliophyta. Flowering plants are plants that grow flowers. Such plants use seeds to reproduce, or make more plants like them.
Seeds are protected in fruits in such kinds of plants.
Examples of flowering plants are daisies, tulips, oaks, apples.
Answer:
Seeds are protected by a fruit
Explanation:
Explain what happens if you change the number of protons in an element?
Plzzz helpppp!!!
Answers
Answer:
When you change the number of protons in an atom, you will change the atom from one element to a different element. Sometimes, when you add a proton to an element, the element will become radioactive. If you change the number of electrons in an atom, you will get an ion of the element.
A force is always a push. true or false ?
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During which process of the water cycle does water change from gas to liquid
Answers
A chemist burns 0.8 g of iron in oxygen.
The iron reacts to form 1.1 g of iron oxide.
Calculate the mass of oxygen that reacted with the iron.
Answers
Answer:
0.3g
Explanation:
1.1 - 0.8 = 0.3
Hope this helps
The mass of oxygen that reacted with the iron is 0.3g
The chemist burns 0.8g of iron in oxygen
the iron reacts to form 1.1g of iron oxide
Therefore the mass of oxygen can be calculated by subtracting the mass of iron in oxygen from the mass of iron
= 1.1 - 0.8
= 0.3g
Hence the mass of oxygen that reacted with the iron is 0.3g
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What is the process called when the moon bagins to fade from full moon to new moon
Answers
PLEASE HELP ME!!
Water (H2O) is composed of the same elements as hydrogen peroxide (H2O2).
Why do these substances have different properties?
The molecules are the same.
Water has more atoms than hydrogen peroxide.
The atoms are arranged differently in each molecule.
The atoms are the same.
Answers
Answer:
The molecules are the same.
Explanation:
What are the seven most abundant elements?
Answers
Answer:
the seven most abundant elements are
oxygen
carbon
hydrogen
nitrogen
calcium
phosphorus
Explanation:
hope this helps
good luck:)
Answer:
oxygen
carbon
hydrogen
nitrogen
calcium
phosphorus
What is the importance of protons ?
Answers
Protons are important because they help keep the nucleus together, they also attract negatively charged electrons and keep them in orbit around the nucleus.
in your own words describe the process of a physical change
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Answer:
A physical change is when the form of an object changes, but the substance stays the same.
Example: Ice melting into water.
which element has an atom with the following composition? 24 protons, 28 neutrons and 24 electrons.
Answers
The amount of protons is equal to the atomic number and this can always be used to identify the element
PLEASE HELP WILL GIVE BRAINLIEST
Answers
This chart shows characteristics of three different types of atoms.
A 3-column table with one row titled valence electrons in three types of atoms. The first column labeled Atom X has entry 6 valence electrons. The second column labeled Atom Y has entry 2 valence electrons. The third column labeled Atom Z has entry 8 valence electrons.
Which statement is best supported by the information in the chart?
Atom X will donate electrons to Atom Y.
Atom X will accept electrons from Atom Y.
Atom Y will accept electrons from Atom Z.
Atom Z will donate electrons to Atom X.
Answers
Atom X will accept electrons from Atom Y.
Answer:
B) Atom X will accept electrons from Atom Y.
Explanation:
because X has 6 electrons and Y has 2 it would make sense for Y to give to X
calculate the oxidation number of s in S2O8^2-
Answers
Given problem:
S₂O₈²⁻
Find the oxidation number of S;
Oxidation number presents the extent of oxidation of each atom of elements a molecular formular or formula unit or an ionic radical.
For radicals:
"the algebraic sum of all the oxidation numbers of all atoms in an ion containing more than one kind of atom is equal to the charge on the ion "
S₂O₈²⁻; oxidation number of O is usually -2
2(S) + 8(-2) = -2
2S - 16 = -2
2S = -2 + 16
2S = 14
S = +7
The oxidation state of S in the radical is +7
the amount of space an object occupies is called its
Answers
All covalent compounds donot exist as giant aggregates. Why?