5. What is a hypothesis and how is it used?
Answer: a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
A hypothesis is used in an experiment to define the relationship between two variables. The purpose of a hypothesis is to find the answer to a question. A formalized hypothesis will force us to think about what results we should look for in an experiment. The first variable is called the independent variable
i hopes this helps :)
Explain the term catalyst and how it affects the rate of a chemical reaction.
Answer:
Catalyst. A catalyst speeds up a chemical reaction, without being consumed by the reaction. It increases the reaction rate by lowering the activation energy for a reaction. Energy diagrams are useful to illustrate the effect of a catalyst on reaction rates.
Explanation:
how many molecules are in CO²
Answer:
53.11× 10²³ molecules
Explanation:
Given data:
Number of molecules of CO₂ = ?
Mass of CO₂ = 388.1 g
Solution:
Formula:
Number of moles = mass/ molar mass
Molar mass of CO₂ = 12× 1 + 16×2
Molar mass of CO₂ = 44 g/mol
Now we will put the values in formula.
Number of moles = 388.1 g/ 44 g/mol
Number of moles = 8.82 moles
Now we will calculate the number of molecules by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ molecules
8.82 mol × 6.022 × 10²³ molecules / 1 mol
53.11× 10²³ molecules
Brainliest plz?
Answer:
Now times by Abogadros constant: 1* 6.022*10^23=6.022*10^23 molecules of CO2 are present.
Explanation:
We know the molar mass of CO2(g) is 44.01⋅g⋅mol−1 . And so Avogadro's number of carbon dioxide molecules have this mass... And we take the product of the quotient... Molecules of carbon dioxide=5.00⋅mol×6.022×1023⋅mol−1≅30×1023⋅carbon dioxide molecules.
Helium gas (He) is an element and not a compound. Why is this true?
A horse traveled a distance of 20 miles in 2
hours. What was the horse's speed?
Answer:
The horses speed was 10 miles per hour.
Explanation:
20/2=10
Hope this helps!
2. Which atom is larger, Na or Al? Explain why.
Answer:
Na
Explanation:
Because it has the highest protons and electrons(Atomic mass)
The hottest place in California is Death Valley with a record temperature of 130 ⁰F. Calculate the temperature in ⁰C and K.
Answer:
54.(4)° C (the 4 in the parentheses means the 4 goes forever), 327.594°K
Explanation:
When you convert 130°F to °C, you will get 54.(4)°C, and the 4 in the parentheses goes forever, and 130°F to °K is 327.594°K, hope it helps!
How has cooperation played a role in life's major evolutionary transitions?
Answer:
The cooperation of a species is shown throughout history. Including in our history. Where it be physical evolution or technological. We have helped each other with building, advice, locations, Reproduction, etc.
Where in equation for photosynthesis does carbon dioxide belong
Answer:
The equation for photosynthesis is 6 CO2 + 6 H2O + light --> C6H12O6 + 6 O2, so carbon dioxide will be found in the reactant part of the equation.
An unknown metal has a density of 10.51 g/ml and a mass of 287.8 g. What is the
unknown metal's volume?
Answer:
27.3834443387 so B
Explanation:
M/D=V
287.8/10.51=V
V=27.3834443387
Answer:
27.38
Explanation:
287.8 Divided by 10.51 = 27.38
Please mark brainliest if helped
The most important ELEMENT found in all living things is
A. Oxygen
B. hydrogen
C. Nitrogen
D. Carbon
Answer:
A. Carbon hope this helps
Answer:
D. Carbon. I guess that's the answer
Which contribution is a modification to Thomson's plum pudding model?
Atoms are indivisible.
Electrons are scattered in an atom.
A positively charged nucleus sits at the center of an atom.
Atoms of the same element have the same properties.
Answer:
Option C: A positively charged nucleus sits at the center of an atom.
Explanation:
Thompson’s plum pudding model was a model proposed by Thompson to show that an atom consisted of more than one fundamental unit.
In Thompson's model, he suggested that the atom consisted of a cloud of positive charges which were surrounded by electrons which are negative charges distributed throughout.
Now, Thompson's experiment was later rejected by Ernest Rutherford when he carried out the gold foil experiment and came to the conclusion where he proposed a model that the atom consisted of mainly empty space and that all its positive charge are concentrated at its center and further surrounded by a cloud of electrons.
From the given options, the correct one is Option C.
Answer: Option C: A positively charged nucleus sits at the center of an atom.
Explanation:
If an unknown sample contains 39.04% sulfuric acid by mass, then a 0.9368 g of that sample would require _____ mL of 0.2389 M NaOH for neutralization.
A) 31.22
B) 39.98
C) 7.80
D) 79.96
E) 15.61
Please give an answer and an explanation, thanks!
Answer:
A) 31.22
Explanation:
The reaction of sulfuric acid with NaOH is:
H₂SO₄ + 2 NaOH → Na₂SO₄ + 2H₂O
To solve this problem we need to determine the moles of acid that will react, and, using the chemical equation we can determine the moles of NaOH and the volume that a 0.2389M NaOH solution would require to neutralize it.
Moles H₂SO₄ (Molar mass: 98.08g/mol):
0.9368g * 39.04% = 0.3657g H₂SO₄ * (1mol / 98.08g) =
3.7289x10⁻³moles H₂SO₄
And moles of NaOH that you require to neutralize the acid are:
3.7289x10⁻³moles H₂SO₄ * (2 moles NaOH / 1 mole H₂SO₄) =
7.4578x10⁻³ moles NaOH
Using a 0.2389M NaOH solution:
7.4578x10⁻³ moles NaOH * (1L / 0.2389mol) = 0.03122L = 31.22mL
Right answer is:
A) 31.22Which one of the following is the symbol used in a chemical equation for a
gas?
A. (g)
B. (aq)
C. (gas)
D. (a)
Answer:
A. (g)
Explanation:
Since it asks for a gas, it is A.
Answer:
A (g)
Explanation:
Which option is a mixture? a.carbon dioxide b. air c. oxygen d. carbon
Answer:
Air
Explanation:
Did test 100
During a change in state, energy is transferred in the form of
heat
light
moisture
motion
Answer:
heat I think.....
Hope it will help you......During a change in state, energy is transferred in the form of heat.
Hence, Option (A) is correct.
What is States of matter ?
When energy is added or removed to matter in the form of heat, it changes state to form a state of matter.
A state of matter is defined as one of the ways in which matter can interact with itself to form a homogeneous phase.
Therefore , During a change in state, energy is transferred in the form
of heat. Hence, Option (A) is correct.
Learn more about States of matter here ;
https://brainly.com/question/9402776
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Which changes involve forming or breaking chemical bonds?
A.burning and digesting
B.boiling and melting
C.burning and melting
D.rusting and cutting
Answer:
d
Explanation:
i took the test
The unknown element (Johnsonium, Jo) contains three naturally occurring isotopes. The relative abundances and atomic mass are:
Moorium-36: abundance = 1.32%, mass = 35.978amu
Moorium-38: abundance = 3.25%, mass = 37.963amu
Moorium-40: abundance = 95.43%, mass = 39.962amu
What is the average atomic mass of "Moorium?"
Answer:
Average atomic mass of moorium is 39.844 amu.
Explanation:
Given data:
Atomic mass of moorium-36 = 35.978 amu
Relative abundance of moorium-36 = 1.32%
Atomic mass of moorium-38 = 37.963 amu
Relative abundance of moorium-38 = 3.25%
Atomic mass of moorium-40 = 39.962 amu
Relative abundance of moorium-38 = 95.43%
Solution:
Average atomic mass moorium = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+ (abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass of moorium = (1.32×35.978)+(3.25×37.963)+(95.43×39.962) /100
Average atomic mass of moorium = 47.491 + 123.380 +3813.574 / 100
Average atomic mass of moorium = 3984.445 / 100
Average atomic mass of moorium = 39.844 amu
Calculate the entropy change when 4.31 g of H2 reacts with O2 according to the reaction
2 H2(g) + O2(g) → 2 H2O(l)
at 298 K and 1 atm pressure. The standard molar enthalpy of formation of H2O(l) at 298 K is −285.8 kJ/mol. The corresponding free energy of formation is −237.2 kJ/mol.
Answer in units of J/K.
Answer:
Explanation:
ΔG = Δ H - T ΔS
Given , ΔG = -237.2 kJ / mol
Δ H = - 285.8 kJ / mol
T = 298
Putting the values in the equation
-237.2 = - 285.8 - 298 x ΔS
ΔS = .163 kJ / mole K
moles of water formed = 4.31 / 2 = 2.155
entropy change required = 2.155 x .163 kJ / K
= 351.26 J / K .
Formula for all possible isomers of hexane
Answer:
1) n-Hexane. 2) 2-Methyl pentane(IUPAC name) or Isohexane(common name). 3) 2,2-Dimethylbutane(IUPAC name) or Neohexane(common name). 4) 3-Methylpentane
Explanation:
Which noble gases is closest to magnesium? On the periodic table? What must happen if a magnesium atom for it to have an electron arrangement similar to that of a noble gas?
Answer:
Neon and loose electrons
Explanation:
Magnesium has an electron configuration of 2e 8e 2e, and Neon is 2e,8e. For Mg to have a similar electron arrangement it must loose its two valence electrons and make it an ion.
Answer:
Noble neon gas is the closest.
Explanation:
noble Neon gas
The Magnesium would have to lose two electrons
What type of reaction is the equation 2NaCl → 2Na +Cl2?
Answer:
Synthesis reaction
Explanation:
This is a synthesis reaction. When you combine sodium metal (Na) with chlorine gas (Cl), you form sodium chloride or kosher salt (NaCl).
Hope this explanation helps!
You come across a mysterious substance that has a mass of 1.8225 x 10 to the power of 2g
and a volume of 0.025 L (1L = 1000 mL). Using the density formula what is the density
Answer:
192
Explanation:
Bc its 182
Explain the term rate of a chemical reaction.
Answer:
The rate of a reaction is a measure of how quickly a reactant is used up, or a product is formed.
Explanation:
Which is a dominant trait that Mendel observed in pea plant
A. Bumpy pods
B. Short height
C. Yellow seeds
D. White flowers
it is not A
Answer:
C, yellow seeds
Explanation:
In Mandel's studies, he proved that yellow seeds were to be dominant and green seeds were to be recessive.
Answer:
c. yellow seeds
Explanation:
i toke the test
Please help I’ll give brainiest!
Answer:
Im sorry if u get it worng but is it the 3rd one?
Explanation:
a sample of alcohol has a density 0.82 g/ml.what is the mass of 5500 mL of the alcohol
Answer:
The answer is 4510 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
density = 0.82 g/mL
volume = 5500 mL
We have
mass = 0.82 × 5500
We have the final answer as
4510 gHope this helps you
Which action would cause the chair to move to the left?
A. Applying 100 N of force to the chair from the left
B. Applying 100 N of force to the chair from the right
C. Applying 200 N of force to the chair from the right
D. Applying 200 N of force to the chair from the left
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What happens to particles in a sample of liquid when the liquid is heated and cooled?
40POINTS AND BRAINLIEST Discuss the orders in which electrons are filled in the s and d subshells of the first three elements in group11
Step 1: add electrons to fill the 1s subshell (maximum of 2 electrons), when this is full, go to step 2. Step 2: add electrons to fill the 2s subshell (maximum of 2 electrons), when this is full, go to step 3. Step 3: add electrons to fill the 2p subshell (maximum of 6 electrons), when this is full, go to step 4. Step 4: add electrons to fill the 3s subshell (maximum of 2 electrons), when this is full, go to step 5. Step 5: add electrons to fill the 3p subshell (maximum of 6 electrons), when this is full, go to step 6. Step 6: add electrons to the 4s subshell (maximum of 2 electrons), when this is full, go to step 7. Step 7: add electrons to the 3d subshell (maximum of 10 electrons), when this is full, go to step 8. Step 8: add electrons to the 4p subshell (maximum of 6 electrons), when this is full, go to step 9. etc
So for Cu would be: 1s^22s^22p^63s^23p^63d^9
Ag would be: 1s^22s^22p^63s^23p^63d^104s^24p^64d^105s^1
Au would be: 1s^22s^22p^63s^23p^63d^104s^24p^64d^105s^25p^64f^145d^106s^1