Catalysts speed up chemical reactions / changes.
Hope this helps!
Which of the following are elements? (Select all that apply.)
KCl
Na
C
H2O
Answer:
Na(Sodium) and C(Carbon) only
Answer:
Na, C
Explanation:
1. KCl, or potassium chloride, is a combination of two elements- so it's a chemical compound.
2. Na, or sodium, can be found on the periodic table of elements. Therefore, it is an element.
3. C, or carbon, can also be found on the periodic table of elements. Therefore, it is an element.
4. H20, or water, is a combination of 2 hydrogen atoms that bonded into an oxygen atom. Combination of 2 or more elements is a chemical compound.
Therefore, the answers are Na and C.
What mass of aluminium is needed to react with 640g of iron oxide
Answer:
13.5g
Explanation:
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 138.8g of aluminium is needed to react with 640g of iron oxide.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.
Mathematically, the balanced equation can be written as
3Fe[tex]_2[/tex]O[tex]_3[/tex] + 4Al [tex]\rightarrow[/tex] Al[tex]_2[/tex]O[tex]_3[/tex] + 6Fe
number of moles of iron oxide= 640/159.6
=4.01
number of moles of aluminium =(4/3)×4.01
=5.34moles
mass of aluminium =5.34×26
=138.8g
Therefore, 138.8g of aluminium is needed to react with 640g of iron oxide.
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Help Please
I Have to finish this assignment asap
Answer:a. limiting reactant
b. actual yield
c. mole ratio
d.excess reactant
e.theoretical yield
f.stoichiometry
g.percent yield
h.limiting reactant
i.theoretical yield
Explanation: ..
I'm horrible at Chem plse help! Determine whether the reaction given below would be spontaneous or not. JUSTIFY your answer.
Mg2+ (aq) + Ag (s) → Ag+ (aq) + Mg (s)
Thank you
Answer:
This is a not a spontaneous reaction.
Explanation:
No, it would not be one because if you add the reactants the products would have to be the same (same types of atoms. number of atoms, and the arrangement of the atoms). In this case the reactants and the products are not equal.
4. Which elements have a completely full outermost energy level?
Answer:
Helium (He), neon (Ne), and argon (Ar), as group 18 elements, have outer electron shells that are full or satisfy the octet rule. This makes them highly stable as single atoms. Because of their non-reactivity, they are called the inert gases or noble gases.
Explanation:
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An experiment was set up so that each test tube contained water at a pH of 6.3 and a pH indicator. Test tubes 1 and 2 also contained a common pond autotroph. Carbon dioxide dissolves in water and forms carbonic acid. After three days the four test tubes were found to have these results.What conclusion can be drawn from test tube 1 and test tube 2
Answer:
I think there was a picture with the results that you need to attach but regardless we need the results.
Explanation:
a. Law of conservation of matter
i. What does the law say about matter?
Write a balanced chemical equation for the standard formation reaction of gaseous hydrogen bromide (hbr)
[tex]\\ \sf\longmapsto H_2+Br_2\longrightarrow HBr[/tex]
Balanced equation[tex]\\ \sf\longmapsto H_2+Br_2\longrightarrow 2HBr[/tex]
On reactant side:-
H=2Br=2On products side
H=2Br=2The balanced chemical equation for the synthesis of hydrogen bromide is [tex]\rm H_2\;+\;Br_2\;\rightarrow\;2\;HBr[/tex].
What is a balanced chemical equation?The balanced chemical equation has been given as the reaction in which the number of atoms for each element on the product and the reactant side is equal.
The HBr has been formed with the reaction of the hydrogen and the bromine. The balanced chemical equation for the reaction has been:
[tex]\rm H_2\;+\;Br_2\;\rightarrow\;2\;HBr[/tex]
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What is phase change? How does matter change in phase?
Answer ASAP pls :(
Answer:
when the chemical composition of a substance change and it is not reversible it is called phase change.for example: turning milk in to yogurt
Plz help I’m pretty confused on this question
Answer:
Bohr model A
Explanation:
It has more valance electrons therefore has more interaction between the atoms and has more electronegativity.
Which of the following typically increases the rate of a chemical reaction? А avoiding the use of a catalyst B heating the reaction C increasing the volume of the reaction vessel D decreasing the concentration of the reactants
B: heating the reaction
hope i could help :D
What is Art Conservation?
Answer:
The conservation and restoration of cultural property focuses on protection and care of cultural property, including artworks, architecture, archaeology, and museum collections. Conservation activities include preventive conservation, examination, documentation, research, treatment, and education
Explanation:
this is the correct answer
Step 2: Predict the Number of Nuclei at Each Half-Life
0.5"
Using the values from Step 1, predict the pattern
for the decay of 100 atoms over the course of eight
half-life cycles, Round to the nearest whole
number of atoms. Record in the appropriate
blanks
Time- Half-
Life Cycles, no
Initial
Radioactive Atoms
(Predicted)
100
1
1
0.5
А
2
0.25
A= 27
25
3
0.125
B
B = 16
4.
0.0625
6
C = 9
5
0.03125
С
D=4
6
0.015625
D
7
0.0078125
1
E
8
0.00390625
E
DONE
) Intro
Answer:
A=50
B=13
C=3
D=2
E=0
Explanation:
I need the circle question to be answered please help me this.
Answer:
(iii):
Reaction 1: Addition
[ We added chlorine to 2-propene ]
Reaction 2: Substitution
[ We substituted hydroxyl ion with chloride ion ]
Reaction 3: Oxidation
[ Acidified permanganate solution is a strong oxidizing agent. So we oxidized propanol to propanoic acid ]
Reaction 4: Acid - base
[ A base (Sodium hydroxide) is added to an acid (propanoic acid) to form a neutral salt ( Sodium propanoate ) ]
2AlCl3 --> 2Al + 3Al2
If you produce 15 moles of Al, how many grams of AlCl3 decomposed?
Answer:
1597,5 gm AlCl3 decomposed
Explanation:
2AlCl3 --> 2Al + 3Al2 If you produce 15 moles of Al, how many grams of AlCl3 decomposed?
FIRST, you need to write down the the correct reaction. Your equation makes no sense
here is the correct question
2AlCl3 --> 2Al + 3Cl2 If you produce 15 moles of Al, how many grams of AlCl3 decomposed?
for every mole of Al produced, we decomposed a mole of AlCl3
so we produced 15 moles of Al, so we decomposed 15 moles of AlCl3
15 moles are 15 X 106.5 = 1597,5 gm AlCl3 decomposed
What can you infer from the fact that nitrogen gas is useless to animals?
Answer:
Denitrification changes nitrogen into a gaseous form.
Explanation:
how many core electrons are there in a sodium atom?
Answer:
There are 13 core electrons in a sodium atom.
for each type of geometry in the simulation, examine the resulting bond angles by clicking the show bond angles checkbox. based on your observations for each geometry, provide the bond angles at the indicated locations for the two-dimensional representations of the three-dimensional structures.
The bond angles in PCl5 are 90° and 180° respectively. The bond angle in NH4^+ is 109°.
Bond angles refer to the angle between two atoms bonded to the same central atom. Several factors such as electronegativity difference and presence or absence of lone pairs on the central atom all affect the bond angle.
For NH4^+, the indicated bond angle is 109° and the specie is tetrahedral. For the specie, SF6, the indicated bond angles are 90° and 180° respectively. For HCN, the indicated bond angle is 180°. For PCl5, the indicated bond angles are 90° and 180° respectively.Learn more: https://brainly.com/question/2192784
help me please?????
count the atoms in the following example
Need answer ASAP
Answer:
32 atoms.
Explanation:
4 x 2 = 8 +
4 x 3(O3) = 12 +
4 x 3(SO3) = 12; 32
A student graphed the position of a cart during a 7-second time interval.
Which statement best describes the cart?
A.
The cart was stationary except for a short burst of acceleration of 0.5 m/s².
B.
The cart accelerated at a constant rate of approximately 0.8 m/s².
C.
The cart was stationary with a velocity of 0 m/s for the entire 7 seconds.
D.
The cart moved at a constant velocity of 0.5 m/s for the entire 7 seconds.
The cart accelerated at a constant rate of approximately 0.8 m/s². Option (B) is correct.
Option B is the best description based on the graphed position data during the 7-second time interval. The cart's acceleration can be determined by analyzing the shape of the position-time graph.
If the cart was stationary, the position-time graph would be a horizontal line (option C). If the cart moved at a constant velocity, the graph would be a straight line inclined at a constant angle (option D).
However, the graph likely shows a curved line, indicating changing position over time. This suggests that the cart experienced acceleration. To further confirm, calculate the acceleration:
Acceleration (a) = Δv / Δt,
where Δv is the change in velocity and Δt is the change in time.
Given the time interval is 7 seconds, and the initial and final velocities are likely different, you can calculate the average acceleration. If the average acceleration is approximately 0.8 m/s², then option B is correct.
The graphed data aligns with the scenario of constant acceleration, supporting option B.
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Study the chemical equation.
Na + Cl2 → NaCl
Is the chemical equation properly balanced?
Salt dissolving in water is an example of what?
chemical change
chemical property
Physical Change
Answer:
chemical change
Explanation:
because chemical chande is a permanent change
What element is being reduced in the following redox reaction? Cr(OH)4-(aq) ClO-(aq) → CrO42-(aq) Cl-(aq).
The element that is being reduced in the given redox reaction is Cl (Chlorine)
The given redox reaction is
Cr(OH)₄⁻(aq) + ClO⁻(aq) → CrO₄²⁻(aq) + Cl⁻(aq)
First, we will define the terms oxidation and reduction
Oxidation can be defined as an increase in oxidation number
Reduction is defined as a decrease in oxidation number
This means the element that is being reduced in the reaction would have a decrease in oxidation number.
Oxidation number of Cr in Cr(OH)₄⁻ is +3; and the oxidation number of Cr in CrO₄²⁻ is +6. This is an increase in oxidation number and it means Cr is being oxidized.
Oxidation number of Cl in ClO⁻ is +1; and the oxidation number of Cl in Cl⁻ is -1. This is a decrease in oxidation number and it means Cl is being reduced.
Hence, the element that is being reduced in the given redox reaction is Cl (Chlorine).
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Which process requires water to gain heat energy from th
environment?
O condensation
O evaporation
infiltration
precipitation
Answer:
Evaporation, please mark me Brainliest
The temprature at which a solid melts is the same as the temprature at which its luqid form solidifies.TRUE OR FALSE.PLS GUYS HELP ME!
Answer:
The statement is true
Explanation:
The temperature at which a solid melts is the same as the temperature at which its liquid solidifies
its answer is true cause the temprature of melting ice is same as the liquid solidifies
What does percent composition tell you about a molecule?
O A. It tells you the ratio of elements in the molecular formula.
OB. It gives you the total number of atoms in the molecule.
C. It tells you how much of a molecule is made up of each element.
O D. It tells you how the elements are arranged in the molecule.
Answer:
C
Explanation:
Why do we fill balloons
with helium gas instead
of oxygen gas?
Answer:
Helium is less dense. Because helium is lighter than air, a helium balloon rises, just as an air bubble rises in more dense water
Explanation:
Also why not. It just is.
Answer:
This is due to the fact that helium has a lower density. A helium balloon rises like an air bubble in more dense water because helium is lighter than air. Another gas lighter than air is hydrogen, which is even lighter than helium.
Explanation:
With which instrument can you measure the mass of a solid?
You can use Balances and Scales..
What’s a conjugative Bas of OH-
Answer:
the answer is O²- hopefully