Which of the following is an indication of a physical change?
O A. The formation of a new substance
O B. Giving off a smell
O C. A change in the shape of a substance
O D. The production of gas and heat
Answer:
A change in the shape of a substance
Explanation:
Because when ths shape of a sunstance changes , its physical appearance changes .A physical change is a change to the physical—as opposed to chemical—properties of a substance. They are usually reversible. The physical properties of a substance include such characteristics as shape (volume and size), color, texture, flexibility, density, and mass.
______elements that have a longer half-life are more _______ than those that have a shorter half-life.
Answer:
Radioactive elements
Stable
Explanation:
Radioactive elements that have a longer half-life are more stable than those that a shorter half-life.
Half-life is the time taken for half of a radioactive element to decay by half of its original composition.
Now, if a substance have a long half-life, it is more stable and takes time to break down. For atoms with a short life, they are highly unstable and breaks down readily and easily.
In the reaction given below, 23.5 grams of iron(III) oxide (Fe2O3) are reacted with excess carbon. What is the theoretical yield of iron metal?
2 Fe2O3 + 3 C --> 4 Fe + 3 CO2
If 14.5 grams of iron are recovered when the reaction is complete, what is the percent yield?
**Both answer should be written as XX.X
Answer:
Theoretical yield = 16.76 g
Percent yield = 87%
Explanation:
Given data:
Mass of iron oxide = 23.5 g
Theoretical yield of iron = ?
Actual yield of iron = 14.5 g
Percent yield of iron = ?
Solution:
Chemical equation:
2Fe₂O₃ + 3C → 4Fe + 3CO₂
Number of moles of iron oxide:
Number of moles = mass/molar mass
Number of moles = 23.5 g/ 159.69 g/mol
Number of moles = 0.15 mol
Now we will compare the mole of iron oxide with iron metal.
Fe₂O₃ : Fe
2 : 4
0.15 : 4/2×0.15 = 0.3
Mass of iron:
Mass = number of moles × molar mass
Mass = 0.3 mol × 55.85 g/mol
Mass = 16.76 g
Percent yield:
percent yield = (actual yield / theoretical yield)× 100
Percent yield = (14.5 g / 16.76 g) × 100
Percent yield = 0.87 × 100
Percent yield = 87%
Answer:
I tried the answer above and it’s correct
Explanation:
please help I need to ace this test
When two atoms attach to each other by sharing electrons it is called a...
A: Covalent bond
B: Ionic bond
C: none of these - atoms can't bond to each other.
D: Nuclear bond
2nd question
Two hydrogen atoms bonded together form a compound
A: True
B: False
3rd question
Water is two hydrogen atoms bonded to an oxygen atom. This is an example of a compound
A: True
B: False
like I said I need help on this and I don't wanna fail
#1: A covalent bond
#2 False
#3True
What are the common characteristics among acidic compounds? Basic?
Answer:
turns blue litmus red
reacts with metal
increase hydrogen concentration
6. Write the full symbol for an atom with 1 proton, 2 neutrons, and 0 electrons.
Answer:
The element hydrogen has the simplest atoms, each with just one proton and one electron. The proton forms the nucleus, while the electron orbits around it.
Explanation:
Calculate the molecular mass of the following mass of the following chemical compound
C6H12O6
24 G/mol
180 gmol
155 g/mol
19 g/mol
Answer:
132g/mol
Explanation:
Given compound:
C₆H₁₂O₆
Molecular mass of the compound.
This is the sum of the atomic masses of the given elements in the compound;
C = 12
H = 12
O = 6
Molecular mass = 6(12) + 12(1) + 6(16) = 180g/mol
The specific heat of a certain type of metal is 0.128 J/(g⋅∘C). What was the intial temperature if 0.305 kJ of heat is added to 94.8 g of metal to reach a temperature of 85.0 ∘C?
The intial temperature : 59.865 °C
Further explanationHeat added :
Q = m . c . ΔT
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
[tex]\tt 305=94.8\times 0.128\times (85-t_1)\\\\85-t_1=25.135\\\\t_1=59.865^oC[/tex]
You are doing math homework and get frustrated and throw the 7 kg book with a force of 47
Newtons. How much acceleration will the book have when you throw it?
Answer:
The answer is 6.71 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
[tex]a = \frac{f}{m} \\ [/tex]
f is the force
m is the mass
From the question we have
[tex]a = \frac{47}{7} \\ = 6.714285...[/tex]
We have the final answer as
6.71 m/s²Hope this helps you
How many moles of Cl2 are needed in order to produce 100.0 grams of FeCl3 given the following
equation: 2 Fe + 3 Cl2 → 2 FeCl3
B
T
Answer:
0.92moles
Explanation:
Given reaction:
2Fe + 3Cl₂ → 2FeCl₃
Mass of FeCl₃ = 100g
Unknown:
Number of moles of Cl₂ needed = ?
Solution:
To solve this problem, we work from the known specie to the unknown.
From the mass of the FeCl₃ given, we can solve for the number of moles of the unknown.
Number of moles of FeCl₃;Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of FeCl₃ = 56 + 3(35.5) = 162.5g/mol
Number of moles = [tex]\frac{100}{162.5}[/tex] = 0.62mole
From the reaction expression;
2 mole of FeCl₃ is produced from 3 moles of Cl₂
0.62 mole of FeCl₃ will be produced from [tex]\frac{0.62 x 3}{2}[/tex] = 0.92mole
The number of moles of Cl₂ = 0.92moles
A neutral atom contains 12 neutrons and 11 electrons. The number of protons in this atom is
(1) 1 (3) 12
(2) 11 (4) 23
Answer:
1
Explanation:
how to know the unknown metal in flame test
Explanation:
The flame test is used to visually determine the identity of an unknown metal or metalloid ion based on the characteristic color the salt turns the flame of a Bunsen burner. The heat of the flame excites the electrons of the metals ions, causing them to emit visible light
We can change the substance chemically by
freezing it.
True or false
if the atomic mass is 14 and the atomic number is 7,how many neutrons do you have?
Answer: 7 neutrons
Explanation: Atomic number refers to the number of protons in the nucleus of the atom. Also you can treat atomic mass as how many particles (protons and neutrons) are in the nucleus of the atom. So for this problem:
14 particles - 7 protons = 7 neutrons (and we know all that's left over is neutrons because we subtracted all the protons)
When 0.25 moles of NH3 are produced according to the reaction below, how many moles of H2 must have reacted?
N2 + 3 H2 --> 2 NH3
O 1.5 moles H2
O 0.38 moles H2
O 0.25 moles H2
O 0.17 moles H2
Answer:
Explanation:
by stoichiometry
nNH3/2=nH2/3
0.25/2=nH2/3
nH2=0.25×3/2
nH2=0.375 mol
so its 0.38 mol
Answer:
I have this quiz rn I will try 0.38 if it is right I’ll edit this and say that
Explanation:
How is the process of photosynthesis essential to sustaining life on Earth?
Answer:
Explanation:
Photosynthesis is important to living organisms because it is the number one source of oxygen in the atmosphere. Without photosynthesis, the carbon cycle could not occur, oxygen-requiring life would not survive and plants would die. ... The importance of photosynthesis in our life is the oxygen it produces
An independent variable is....
A: What we measure
B: What we change
C: What stays the same
D: What we conclude
Answer:
B - What we change
Explanation:
Dependent Variable - What we measure
Control Variable - what stays the same
Conclusion - what we conclude
Hope this can Help!
:D
Which screw would create a strong hold?
A: The screw with 9 wraps.
B: The screw with 2 wraps.
C: The screw with 10 wraps.
D: The screw with 6 wraps.
Answer:
The screw with 10 wraps is the correct answer
Explanation:
The screw with 6 wraps would create a strong hold.
What do you mean by screw?The strongest member of the family of wood screws is a lag screw. It is a reliable and sturdy fastener that frequently has a square head or an externally powered hex drive.
In general, lag screws are significantly stronger and heavier than standard wood screws. They have a tapered point and coarse threads.
Thus, The screw with 6 wraps would create a strong hold.
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What else is produced during the combustion of butane, C4H10?
2C4H10 + 13O2 8________ + 10H2O
Answer:
CO2
Explanation:
What is the name of the group that contains potassium?
O Noble Gases
O Halogens
O Alkaline Earth Metals
O Alkali Metals
Transition Metals
Answer:
Alkali Metals
Explanation:
Can someone help? Ill give brainliest!
Directions: count each side of the reaction then Circle yes or no if it follows the law of conservation of mass
Answer:
Explanation:
before the reaction you have K=2 and Cl=4
after the reaction K=2 and Cl=2 so it does not follow the law of conservation
Help me with homework.
The chemical equation is said to be balanced if the number of atoms in the reactants and products is the same
Further explanationEquation balanced ⇒ total number of atoms in reactants(on the left)= total number of atoms in products(on the right)
H₂+O₂---> H₂O
Reactants : H₂, O₂
Products : H₂O
not balanced
H₂O₂ ---> H₂O+O₂
Reactants : H₂O₂
Products : H₂O, O₂
not balanced
Na+O₂ ---> Na₂O
Reactants : Na, O₂
Products : Na₂O
not balanced
N₂+H₂ ---> NH₃
Reactants : N₂, H₂
Products : NH₃
not balanced
P₄+O₂---> P₄O₁₀
Reactants : P₄, O₂
Products : P₄O₁₀
not balanced
Fe+H₂O ----> Fe₃O₄ + H₂
Reactants : Fe, H₂O
Products : Fe₃O₄
not balanced
how many sig figs are in 0.0093
Answer:
there are two significant figures
Explanation:
Answer:
there are two
Explanation:
because the zeros dont count
Why are ocean currents important to coastal regions?
Answer:
Warm and cold ocean currents can affect the climate of an area along the coast if the winds blow in from the ocean. Warm ocean currents heat the air above the water and carry the warm air to the land, increasing the temperature of the coastal region.
Explanation:
Ocean currents are important to coastal regions for a number of reasons.
What are the importance?Distribute heat. Ocean currents distribute heat around the globe, which helps to moderate the climate in coastal regions. For example, the Gulf Stream brings warm water from the Gulf of Mexico to the coasts of Europe, which helps to keep Europe's climate warmer than it would be otherwise.
Transport nutrients. Ocean currents transport nutrients from the ocean's depths to the surface, which supports marine life. For example, the California Current brings nutrients from the deep ocean to the surface, which supports a rich marine ecosystem off the coast of California.
Diversify marine life. Ocean currents help to diversify marine life by transporting different species to different parts of the ocean. For example, the Kuroshio Current brings warm water from the western Pacific Ocean to the eastern Pacific Ocean, which has helped to diversify the marine life in this region.
Find out more on coastal regions here: https://brainly.com/question/26796424
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Record the mass of the object based on the reading from the triple-beam balance. The mass of the object is ____ grams.
Hello!
[tex]\large\boxed{167g}[/tex]
Looking at the balance, we see that:
The middle beam reads 100g.
The top beam reads 60g.
The bottom beam reads 7g.
Add all of the numbers together to get the total mass:
100 + 60 + 7 = 167g.
The mass of the object is 167 grams.
Explanation:
A triple beam balance is a mass measuring instrument used in labs to measure the mass of a substance. It unit in which it measures is grams. It consists of three beams which are: The middle beam has Increments of 100 grams The front beam has Increments from 0 grams to 10 grams The farther beam has Increments of 10 gramsGiven :
Readings of all the scales of three beams of the triple beam balance of an object.
To find :
The mass of object whose reading on triple beam balance is given.
Solution:
Middle beam reader at 100 grams
Front beam reader at 7 grams
Farther beam reader at 60 grams
The mass of object:
[tex]100 grams + 7 garms + 60 grams = 167 grams[/tex]
The mass of the object is 167 grams.
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13 Apply Place a check mark in the box to indicate
which type of mutation is being shown.
Original sequence
deletion insertion substitution
deletion insertion substitution
deletion insertion substitution
Answer:
A. ✔️Substitution
B. ✔️Insertion
C. ✔️Deletion
Explanation:
In A, the type of mutation that is shown is Substitution. In B, the type of mutation shown is Insertion and in C, the type of mutation shown is Deletion.
Mutation refers to the change in the DNA sequence. This occurs in an organism. In gene mutation, the structure of DNA molecule changes and produces a different allele of a gene. While in chromosome mutation, there is the change in the structure or number of the whole chromosomes in a particular cell.
Actually, mutations can take place both in prokaryotic cell and in eukaryotic cell.
In genetics, there are: Substitution, Insertion and Deletion mutations.
Substitution mutation is an exchange of one base for another. Insertion mutation is simply addition of one or more nucleotide pairs in a DNA sequence while Deletion mutation refers to the situation in which a sequence of DNA is left out when there is DNA replication.
Answer:
A. Substitution
B. Insertion
C. Deletion
Explanation:
A. There is a replacement in C G there is A T.
B. There is one more base.
C. There are 8 base there should be 9.
Plzzzzzzzz help Which species is a index fossil
Answer:
e
Explanation:
it's in the index fossil range
Answer:
Explanation:
In marine strata, index fossils that are commonly used include the single-celled Protista with hard body parts and larger forms such as ammonoids. In terrestrial sediments of the Cenozoic Era, which began about 65.5 million years ago, mammals are widely used to date deposits.
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10. The molar mass of CS2 is 76.14 g/mol. How many grams of CS2 are present in 10.00 mol?
Answer: C
Explanation:
There are 761.4 grams of CS2 in 10.00 mol.
To calculate the amount of grams present in a given amount of moles, the molar mass of the substance must be used, as follows:
[tex]m = MM \times mol[/tex]
In this way, just perform the following operation:
[tex]m = 76.14 \times 10[/tex]
[tex]m = 761.4 grams[/tex]
Thus, there are 761.4 grams of CS2 in 10 mol of the substance.
Learn more about mole calculation in: brainly.com/question/15693285
Which of the following most likely happens when thermal energy is removed from a chemical reaction?
Answer:
fewer collisions occur between particles or lowering the temperature
Explanation:
2. How can glass be a liquid if it's so hard?
Explanation:
Glass is not a liquid in the strictest sense of the word. But it is also not a standard solid. The chemistry of glass is complex and research is ongoing, but the current consensus is that glass is a phase of matter all its own, known as an "amorphous solid". Scientists refer to any amorphous solid as a "glass". Glass transitions are highly complex and cannot be treated in the same way as traditional phase transitions.
Answer:
It's a liquid state before its cooled.