Answer:
Indicates the writer's stance on the main idea of a paragraph. The controlling idea appears in the paragraph's topic sentence. ... The final sentence of a paragraph that summarizes the topic sentence using different words. Words and phrases that show how the ideas in sentences and paragraphs are related.
Explanation:
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PICK ME AS THE BRAINLIEST
Answer:
he last paragraph relates to the main topic because the main topic is about cells and the last paragraph is saying how scientist are still discovering cells but the author says that the new cells are not listed in the article
Explanation:
i had a bad day i hope you have a good one -me ;
on June 21st the rays of the sun fall directly on the Tropic of Cancer true or false pls tell the ans and I follow u
Answer:
True
Explanation:
it does! because of the angle between Saturn and Earth and the Sun.
Hope this helps plz hit the crown :D
1. List three factors that can cause a chemical reaction to proceed faster.
2. Raising the temperature of a reaction mixture is the same as increasing the______of the reacting molecules.
3. A student mixes compound A with compound B and notices that a chemical reaction occurs. The temperature of the mixture decreases. The reaction is ________.
4. The temperature of the mixture decreases. The reaction is. Reactions that release energy, like the burning of coal, are called:______.
A. Thermodynamic.
B. Exothermic.
C. Endothermic.
D. Thermotropic.
E. Ergonomic.
5. Which of the following is an endothermic process?
A. Freezing of water.
B. Evaporation of water.
C. Explosion of dynamite.
D. Burning wood.
E. Metabolism in animals.
Explanation:
1. The three factors are;
- Increasing the surface area of the reactants
- Using a catalyst
- Increasing temperature
2. Raising the temperature of a reaction mixture is the same as increasing the kinetic energy of the reacting molecules.
3. This reaction is an exothermic reaction. In exothermic reaction, the temperature of the system (mixture) decreases while that of the surroundings increases.
4. Reactions that releases energy to the surroundings are exothermic reactions.
5. All the options is an example of exothermic process because heat is being removed from the system except;
B. Evaporation of water - This is because it must absorb heat from the surroundings making it endothermic.
PLEASE HELP!!! I'll give brainliest answer
Answer:
1. MG
2. N
3. F
4. NA
5. O
6. K
Answer:
Largest to Smallest: Na, K, Mg, N, O, F
Explanation:
How much water must be added to 15 ml of a 2.5 M solution of sodium chloride to make a 2.0 M solution of sodium chloride?
Answer:
3.75mL need to be added
Explanation:
M1 x V1 = M2 x V2
so V2=(M1xV1)/M2
(2.5Mx.015L)/2M= .01875L or 18.75ml
since we want to know how much needs to be added we subtract 18.75 from 15
Giving us 3.75ml need to be added
How many grams are in 0.040 moles zirconium (Zr)?
Answer:
91.224 gram
Explanation:
Answer:
3.64896 grams Zr
Explanation:
Given: amount of moles of Zr: 0.040
Find: the amount of grams of Zr
1. Find molar mass of Zr
- after looking at the periodic table, you can tell it's 91.224 g/mol
2. Solve
([tex]\frac{0.040 mol Zr}{1}[/tex])( [tex]\frac{91.224 g Zr}{1 mol Zr}[/tex])
- the mol units get cancelled out, and you're left with 0.040 x 91.224 g
3. Multiply that out: 3.64896 grams of zirconium
Liquid hexane CH3CH24CH3 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O
Suppose 0.862 g of hexane is mixed with 5.1 g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Be sure your answer has the correct number of significant digits.
Answer:
2.64g of CO₂ are produced
Explanation:
The reaction of hexane with O₂ is:
C₆H₁₄ + 19/2O₂ → 6CO₂ + 7H₂O
To solve this question, we must convert each mass of reactant to moles in order to find limiting reactant and, with the chemical reaction we can find the moles of carbon dioxide produced and the maximum mass produced:
Moles hexane -Molar mass: 86.18g/mol-:
0.862g * (1mol / 86.18g) = 0.01 moles
Moles Oxygen -Molar mass: 32g/mol-:
5.1g * (1mol / 32g) = 0.16 moles
For a complete reaction of 0.01 moles of hexane there are required:
0.01moles hexane * (19/2 Oxygen / 1mol Hexane) = 0.095 moles oxygen
As there are 0.16moles, limiting reactant is hexane.
0.01 moles of hexane produce:
0.01 moles * (6 moles carbon dioxide / 1 mole hexane) = 0.06 moles of CO₂.
The mass is -Molar mass CO₂: 44g/mol-:
0.06 moles of CO₂ * (44g/mol) =
2.64g of CO₂ are produced
What type of chemical reaction is the following? 2 Fe + O2
Single replacement
Double replacement
Decomposition
Synthesis
O Combustion
Answer:
Synthesis
Explanation:
consider a block G with mass of 49.231 g and a volume of 23.8 ml what is its density
Answer:
ρ = 2.07 g/mL
Explanation:
Step 1: Given data
Mass of the block G (m): 49.231 gVolume of the block G (V): 23.8 mLStep 2: Calculate the density (ρ) of the block G
The density is an intrinsic property, equal to the mass of the block divided by its volume.
ρ = m/V
ρ = 49.231 g/23.8 mL
ρ = 2.07 g/mL
The density of the block G is 2.07 g/mL.
Explain why atoms would gain or lose electrons in order to resemble the elements in the particular group you named above. Consider what you learned about elements in that group.
Answer:
The number of electrons in the outermost shell of an element is represented in the periodic table as the group number that element is situated in the number of electrons in all shells of an element is represented in the periodic table as the element's atomic number.
Explanation:
I hope that helps
Atoms gain or lose electrons to become stable by achieving octet in their valence shell. The number of electrons lost or gain is dependent upon the number of valence electrons.
What are groups in periodic table?The vertical columns in periodic table is called groups and the horizontal rows are called periods. A group contains elements with same number of valence electrons and similar chemical and physical properties.
According to octet rule, atoms when achieve 8 electrons in their valence shell become stable. Thus when atoms have extra electrons or deficient of electrons will lose or gain electrons to attain octet.
Metals in the left side of periodic table are all electropositive and will lose their extra valence electron. Whereas, non-metals are electron - deficient needs to gain electron into their valence shell.
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Question 15 (1 point)
When a toy car is wound up and released on a tile floor, It accelerates as shown in the diagram. What is the force in Newtons that the car's
wheels exert on the floor when it is released?
Acceleration = 0.5 m/s2
Mass = 1.0 kg
Оа
Ob
Ос
Od
0.05N
0.5 N
SN
50 N
Answer:
Option B. 0.5 N.
Explanation:
Data obtained from the question include:
Mass (m) = 1 Kg
Acceleration (a) = 0.5 m/s²
Force (F) =?
Force is defined as the product of mass (m) and acceleration (a). Mathematically, it is expressed as:
Force (F) = mass (m) × acceleration (a)
F = ma
Using the above equation, we can obtain the force exerted on the floor as follow:
Mass (m) = 1 Kg
Acceleration (a) = 0.5 m/s²
Force (F) =?
F = ma
F = 1 × 0.5
F = 0.5 N
Thus, the car exerted a force of 0.5 N on the floor.
3.124. X-ray Absorption Spectroscopy Electrons in multielectron
atoms absorb X-rays at characteristic energies, leading to
ionization. The characteristic energies for each element allow
scientists to identify the element. For magnesium, X-rays
with λ = 952 pm are required to selectively eject an electron
A
from the n = 1 energy level, and X-rays with λ = 197 nm
remove an electron from the n = 2 energy level.
a. Calculate the frequency and energy of those X-rays.
b. Why are the wavelengths and energies different for the
two electrons?
c. In terms of Bohr's values of n, what transitions do those
represent?
Answer:
ddddddddddddedewxdedww
Explanation:
ddddddddddddddddddddddd
Select the correct answer.
Which particles make up the nucleus of an atom?
A.
protons and electrons
B
neutrons and electrons
с.
protons only
D
protons and neutrons
E.
neutrons only
why can an object with balanced forces still be in motion/
Answer:
Diagram A: Balanced Forces
These forces are balanced, so the motion of the object stays the same. The object in the diagram could be sitting still, or it could be moving. But its motion is not changing. This is because the forces acting on it from opposite sides are exactly the same size.
Explanation:
Answer:
Because a balanced force can keep an object moving at a constant velocity.
Explanation:
How many neutrons does this atom have?
04
O 6
O 10
O 14
plzzzz i need help i will give 50 points
Answer:
c maybe if right plz mark brainliest
Explanation:
Answer:
14
Explanation:
it 14 there are 14 neutrons
1. Define the units for molarity. Page |152 Exp. 14 pH and Solutions Pre Lab Questions (1 of 1) 2. A solution contains 5.25 grams of sodium chloride in 750.0 mL of solution. Determine the molarity of the solution. Na
Answer:
1. mol/L
2. 0.120 M
Explanation:
1. Molarity is equal to the moles of solute divided by the liters of solution. The units of molarity are mol/L.
2.
Step 1: Given data
Mass of sodium chloride (solute): 5.25 gVolume of solution (V): 750.0 mL = 0.7500 LStep 2: Calculate the moles of solute (n)
The molar mass of NaCl is 58.44 g/mol.
n = 5.25 g × 1 mol/58.44 g = 0.0898 mol
Step 3: Determine the molarity of the solution
We will use the definition of molarity
M = n/V
M = 0.0898 mol / 0.7500 L = 0.120 M
When glucose is oxidized the product is
Select one:
O a. gluconic acid
b. sucrose
c. galactose
d. glucitol
O e. maltose
Answer:
the answer is C galactose
Answer:
a. gluconic acid
Explanation:
If you have a gold coin that contains 0.637 moles of gold, how many grams of gold does it contain?
Synthesis of cholesterol takes place in the
Oliver.
gall bladder
small intestine.
large intestine.
pancreas.
According to kinetic theory, which two factors are important for a successful
reaction to occur?
A. Collisions between particles with the right orientation
B. Collisions between particles with sufficient energy
C. Collisions between particles with the right concentrations
D. Collisions between particles with sufficient mass
The two factors for a successful reaction to occur are collisions between particles with the right orientation and sufficient energy (A and B).
What is the kinetic theory?The kinetic theory is a model explaining the movement (motion) of particles in a given substance.
This theory (kinetic theory) is used to explain the thermodynamic features of gaseous particles.In conclusion, the two factors for a successful reaction to occur are collisions between particles with the right orientation and sufficient energy (A and B).
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How many hybrid orbitals are found in CCl4? o one o two o three o four
Answer:
I Believe it is 4 orbitals s,p,p,p or aka sp^3
Explanation:
Answer:
Four because its hybridization is SP3 which means one s and three p orbitals combine to form hybrid orbitals
Explanation:
The Al2O3 crystal structure (corundum) consists of an HCP arrangement of O2- ions; the Al3 ions occupy octahedral positions. What fraction of the available octahedral positions are filled with Al3 ions
Answer:
2/3
Explanation:
Crystals structures can also be seen when two elements combines together and the perfect example is Al₂O₃ which is given in the question above. Just like it is given in the question above, the kind of arrangement in the crystal structure for Al₂O₃ is called HCP which stands for Hexagonally Closed Pack.
The aluminum ions which is in form of Al³⁺ occupies the two-third[2/3] positions while the position that the oxygen ion occupies is one[1].
Hydrogen gas H2 is the least dense of all gases. A sample of H2 gas is found to occupy a volume of 1.23 L at 755 mmHg and 0 ◦C. What volume , in liters, will this same gas occupy at .97 atm and a temperature of 50 ◦C.(10 points)
Please include equation used, variable you solved for and answer with correct units
Answer:
V₂ = 1.48 L
Explanation:
Given data:
Initial volume = 1.23 L
Initial pressure = 755 mmHg (755/760 =0.99 atm)
Initial temperature = 0 °C (0 +273 = 273 K)
Final temperature = 50°C (50+273 = 323 K)
Final volume = ?
Final pressure = 0.97 atm
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
Solution:
V₂ = P₁V₁ T₂/ T₁ P₂
V₂ = 0.99 atm × 1.23 L × 323 K / 273 K × 0.97 atm
V₂ = 393.32 atm .L. K / 264.81 atm.K
V₂ = 1.48 L
my brain hurts. halp
Answer:
the answer is C ( i hope your teacher explains
Bohr's model was correct in assigning energy levels to electrons.
Answer:
yes that is true........
Metals are what proportion of the periodic table? *
1/4
2/3
1/2
3/4
what is the mass of 0.82 mol of the element potassium (K)? answer in units of g.
molar mass of potassium is 39.0983 g/Mol
using conversion factors
0.82 Mol K (39.0983 g/ 1 mol)
mol cancels out, leaves you w grams
answer: 32.1 grams K
My friend gave a speech on democracy.
This sentence has one abstract and two concrete nouns. are is true or false
Answer:
True
Explanation:
Nouns are words we use to name everything that surrounds us, for example, people, animals, places, things, etc.
Concrete nouns are nouns we use to name things we can detect by our senses (sight, hearing, taste, smell, and touch). The given sentence contains two concrete nouns - friend and speech.
Abstract nouns are nouns we use to name things that are not concrete, things we can't detect by our senses, for example, qualities, feelings, concepts, ideas, etc. The given sentence contains one abstract noun - democracy.
what mass of iron sulfide is obtained if 8 grams of sulfur and 28 grams of iron are taken for the reaction?
Mass of iron sulfide obtained : 22 g
Further explanationReaction
Fe+S⇒FeS
8 grams of sulfur and 28 grams of iron are taken for the reaction
Find limiting reactantmol of Fe(Ar=56 g/mol) :
[tex]\tt mol=\dfrac{mass}{Ar}\\\\mol=\dfrac{28}{56}\\\\mol=0.5[/tex]
mol of S(Ar=32 g/mol) :
[tex]\tt mol=\dfrac{8}{32}=0.25[/tex]
Limiting reactant ⇒ S(smaller mol ratio), excess reactant : Fe
mol of FeS based on limiting (S) ⇒0.25(mol ratio from equation = 1 : 1)
Mass FeS(MW=88 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=0.25\times 88\\\\mass=22~g[/tex]
Scientific notation.
Answer:
23.1 x 10^11
Explanation:
(4.2x5.5) x (10^9x10^2)
23.1 x 10^11 (Add the exponents, and multiply the decimals.)
I hope this helped! :)
What type of materials are attracted to a magnet?
Answer:
Magnets are only attracted to special metals. Iron, cobalt and nickel are magnetic. Metals that have iron in them attract magnets well. Steel is one.
Explanation: