Which major scientist major contribution was to develop the theory of evolution? (100 points)
Answer:
Alfred Russel Wallace
Compare and contrast cations and anions and give an example of each.
Cations are positively charged particles while anions are negatively charged particles. They both have different forces therefore they are attract each other.
What is cation ?
Positively charged ions are known as cations. Negatively charged ions are referred to as anions. A charged atom or molecule is an ion. A balanced atom will become a positively charged cation if it loses one or more electrons.
An ion that has lost one or more electrons and now has a net positive charge is said to be a cation. The cation of an atom is smaller than the neutral atom because one or more electrons are taken out to produce a cation.
As an electron donor, the cathode has the potential to initiate reduction. Positive ions from the solution will be drawn to the negatively charged electrode by its charge. It can provide some of the extra electrons it has to these cations or other species in the electrolyzing liquid.
Thus, Cations and anions both have different forces therefore they are attract each other.
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what is chemical equilibrium and Le chatelier's principle
Le Chatelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium. If a chemical reaction is at equilibrium and experiences a change in pressure, temperature, or concentration of products or reactants, the equilibrium shifts in the opposite direction to offset the change.
In Chemical reaction, the concentration of reactant and products shows no net change over the time is called as chemical equilibrium.
A town is looking at multiple solutions for its beach erosion problem. Which factors of beach nourishment should the town consider when making a decision? Select the two correct answers.(1 point)
how they will pay for the cost of the project
how long beaches will be closed during the project
how many people drive near the beaches
how long it will take the new sand to dry
how cold the water temperature is at the time of pumping
Answer:
d
Explanation:
The factors of beach nourishment should the town consider to tackle erosion problem include:
how long it will take the new sand to dry.how cold the water temperature is at the time of pumping.What is erosion?It should be noted that erosion simply means the washing away of the top soil by erosional agents.
In this case, the town should take into consideration how long it will take the new sand to dry and how cold the water temperature is at the time of pumping. This is important to replenish lost nutrients.
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Brittleness
Hardness
Elasticity
Conductivity
Biodegradability
1. Ability to break easily.
2. Ability to decomposed by microorganism.
3. Ability to let the heat and electricity to pass through.
4. Ability to be stretched and return to its original shape.
5. Ability to resist pressure that may cause deformation.
Answer:
BrittlenessBiodegradableConductivityElasticityHardnessCan I get BRAINLIEST.... Please
2. Calculate the de Broglie wavelength of an electron moving at 1/137th the speed
of light. (At this speed, the relativistic correction to the mass is negligible
Explanation:
speed of light is 3×10^8 m/ s
1/137 of 3 × 10^ 8 m/s ( u get the speed the electron was moving with)
mass of electron 9.109× 10^-31 kg( i think we consider the mass of electron if the relativistic correction of the mass is negligible)
then from de Broglie wavelength= h/ mv
h is planck constant 6.626 × 10^-34
substitute the valies and you get the answer
am sorry I don't have my calculator with me I wuld hv written the answer bt I hope this helps
The de Broglie wavelength of an electron moving at 1/137th the speed of light is 0.24 × 10¹¹m.
What is de Broglie wavelength ?The term de Broglie wavelength defined as the wavelength (λ) that is associated with an object in relation to its momentum and mass.
De Broglie wavelength is mostly represented by the symbol λ or λdB. For a particle with momentum p, the de Broglie wavelength is known as λdB = hp. where h is the Planck constant.
The speed of light = 3×10^8 m/ s
1 / 137 × 3 × 10^ 8 m/s
The mass of electron 9.109× 10^-31 kg
then from de Broglie wavelength
= h / mv
Where,
h is Planck constant 6.626 × 10^-34
substitute the values in above equation
We get,
= 6.626 × 10⁻³⁴ / 9.109 × 10⁻³¹ × 3×10⁸
= 0.24 × 10¹¹m
Thus, The de Broglie wavelength of an electron moving at 1/137th the speed of light is 0.24 × 10¹¹m.
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how many hydrogen atoms would be present in 12 molecules of water (h2o)?
3
2
24
12
Answer:
Two water molecules contain 4 hydrogen atoms and 2 oxygen atoms. A mole of water molecules contains 2 moles of hydrogen atoms and 1 mole of oxygen atoms.
Explanation:
which property of physical changes explains why matter is conserved in a physical change
Answer:
b
Explanation:
A mixture contains NaHCO3 together with unreactive components. A 1.75 g sample of the mixture reacts with HA to produce 0.561 g of CO2. What is the percent by mass of NaHCO3 in the original mixture?
Answer:
[tex]\%NaHCO_3=61.2\%[/tex]
Explanation:
Hello.
In this case, since the undergoing chemical reaction is only between the sodium bicarbonate and the acid HA:
[tex]NaHCO_3+HA\rightarrow NaA+H_2O+CO_2[/tex]
For 0.561 g of yielded carbon dioxide (molar mass 44 g/mol), the following mass of sodium bicarbonate (molar mass 84 g/mol) that reacted was:
[tex]m_{NaHCO_3}=0.561gCO_2*\frac{1molCO_2}{44gCO_2} *\frac{1molNaHCO_3}{1molCO_2} *\frac{84gNaHCO_3}{1molNaHCO_3} \\\\m_{NaHCO_3}=1.071g[/tex]
Considering the 1:1 mole ratio between CO2 and NaHCO3. Finally, the percent by mass of NaHCO3 is computed by dividing the mass of reacted NaHCO3 and t the mixture:
[tex]\%NaHCO_3=\frac{1.071g}{1.75g}*100\%\\ \\\%NaHCO_3=61.2\%[/tex]
Best regards.
A 1.75 g sample of the mixture of NaHCO₃ together with unreactive components, that reacts with HA to produce 0.561 g of CO₂, has 61.1% by mass of NaHCO₃.
Let's consider the reaction between NaHCO₃ and HA (generic acid).
NaHCO₃ + HA → NaA + H₂O + CO₂
We can calculate the mass of NaHCO₃ that produced 0.561 g of CO₂ using the following conversion factors:
The molar mass of CO₂ is 44.01 g/mol.The molar ratio of NaHCO₃ to CO₂ is 1:1.The molar mass of NaHCO₃ is 84.01 g/mol.[tex]0.561gCO_2 \times \frac{1molCO_2}{44.01gCO_2} \times \frac{1molNaHCO_3}{1molCO_2} \times \frac{84.01gNaHCO_3}{1molNaHCO_3} = 1.07 g NaHCO_3[/tex]
There are 1.07 g of NaHCO₃ in 1.75 g of the mixture. The percent by mass of NaHCO₃ in the mixture is:
[tex]\%NaHCO_3 = \frac{1.07g}{1.75g} \times 100\% = 61.1\%[/tex]
A 1.75 g sample of the mixture of NaHCO₃ together with unreactive components, that reacts with HA to produce 0.561 g of CO₂, has 61.1% by mass of NaHCO₃.
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