answer is a
Explanation:
What dose the T-cell attack
Answer:
killer T-cell find and destroy infected cells that have been turned into virus-making factories
Acid rain due to air pollution when water reacts with sulfur dioxide, nitric oxide, and carbon dioxide, causes
Answer:
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.
Explanation:
what particle has a mass & charge?
a. alpha particle
b. beta particle
c. gamma ray
Answer:
A. Alpha Particle
Explanation:
I think i could be wrong
Silicon can be made by heating a mixture of sand (silicon dioxide) with magnesium
powder.
The equation for this reaction is shown below.
SiO2 (s)+ 2Mg (s) → 2MgO (s) + Si (s)
Calculate the mass of silicon dioxide needed to make 1 g of silicon.
Relative atomic masses: O = 16; Si = 28
Mass = ?
Answer:
[tex] \frac{60}{28} = \frac{15}{7} [/tex]
A photon with a wavelength of 397nm is emitted from an electron in energy level 7 of a Hydrogen atom. What is the new energy level of the electron?
Answer:
New energy level is n = 2
Explanation:
ΔE = energy released by e⁻ transition n = 7 to n(final) = - h·c/λ
h = Planck's Constant = 6.63 x 10⁻³⁴ j·s
c = speed of light in vacuum = 3 x 10⁸ m/s
λ = wavelength = 397 nm = 3.97 x 10⁻⁷ m
ΔE = - (6.63 x 10⁻³⁴j·s )(3 x 10⁸ m/s)/(3.97 x 10⁻⁷ m) = - 5.01 x 10⁻¹⁹ joule
Note: this is the transitional energy 'released' by the electron moving from n = 7 energy level to n(final) energy level. As released energy, the system should be represented by an exothermic process hence, the negative value for ΔE = - h·c/λ. The equivalent amount of energy is an absorption of electromagnetic energy (EMR) to promote the electron from n(final) to n = 7 and this would be endothermic as noted with a +h·c/λ .
The Bohr Model of the electron behavior postulates electron transitions by the release of a 'discrete' amount of EMR as emission spectra defined by the expression ...
ΔE = E(final) - E(initial) => E(final) = ΔE + E(initial)
E(n) = positional (potential) energy content of electron while in energy level n and is defined by the expression E(n) = -R(H)/n²
R(H) = Rydberg Constant = 2.18 x 10⁻¹⁸ joules
n = positional energy level (in this case) = 7
E₇ = -2.18 x 10⁻¹⁸ j / (7)² = -4.45 x 10⁻²⁰ j (potential energy of n = 7 electron)
E(final) = ΔE + E₇ = (-5.01 x 10⁻¹⁹ j) + (-4.45 x 10⁻²⁰ j) = -4.455 x 10⁻¹⁹ j
E(final) = -R(H)/n²
=> n = SqrRt[R(H)/E(final)] = SqrRt[(-2.18 x 10⁻¹⁸ j)/(-4.455 x 10⁻¹⁹)] ≅ 2
New energy level is n = 2
help please and show work!
Answer:
Mg + 2HCl → MgCl2 + H2
Explanation:
Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2
How does energy from the Sun drive the cycling of matter?
Answer:
solar energy drives the cycle by evaporating water from the oceans, lakes, rivers, and soil. As liquid water evaporates or transpires, it forms water vapor and clouds, where water droplets eventually gain enough mass to fall back to Earth as precipitation.
______________________________ is the attraction amongst molecules that are dissimilar.
A.) Transpiration
B.) Cohesion
C.) Adhesion
D.) Polarity
Answer:
ily
Explanation:
which two things cause the orbits of the planets to be the nearby circular
Inertia
gravity
electricity
magnetism
Answer:Gravity and inertia
Which solute, an electrolyte or a nonelectrolyte, has the greater effect on the boiling point when a given amount of each
solute is dissolved in the same mass of water?
O The nonelectrolyte does because it disperses into molecules.
O The electrolyte does because it disperses into molecules.
O The nonelectrolyte does because it dissociates into ions.
O The electrolyte does because it dissociates into ions.
The solute wether electrolyte or a nonelectrolyte, has the greater effect on the boiling point when a given amount of each solute is dissolved in the same mass of water The nonelectrolyte does because it dissociates into ions.
What is a solute?Solute refers to substances or liquid which can readily dissolve in a solvent. It's concentration is lower to that of solvent.
Therefore, The solute wether electrolyte or a nonelectrolyte, has the greater effect on the boiling point when a given amount of each solute is dissolved in the same mass of water The nonelectrolyte does because it dissociates into ions
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Answer:
D: The electrolyte does because it dissociates into ions.
Explanation:
HELPP asap I’ll mark you as brainlister
Answer:
The solution is nopolar
Explanation:
Answer:
The solution does NOT conduct electricity.
Explanation:
Nonelectrolytes are usually held together by covalent bonds rather than ionic ones.
C time
2. An instrument used to measure force is
B. spring balance
A ruler
D) wind vane
C. thermometer
of ford
Answer:
B. Spring balance - a device used for measuring the weight or force of gravity acting on an object.
Explanation:
A Force is any interaction that changes the motion or position of an obkpjectbthatbit is interacting with. Whenever there is an interaction between two objects, there is a force exerted by each of the objects on one themselves.
Forces are generally divided into contact forces and non-contact over field forces.
In contact forces, the two objects physically in contact with each other. Examples of contact forces are push or pull forces, frictional forces, tensional forces, spring forces, etc.
Non-contact forces are forces in which the two objects interacting do no need to be physically in contact with one another. Examples include, gravitational forces, magnetic forces, electrical forces, etc.
Instruments used in measuring forces are known as force gauges.
From the instruments listed above:
A. A ruler is an instrument used in measuring length
B. Spring balance is a device used for measuring the weight or force of gravity acting on an object.
C. A thermometer is an instrument used in measuring temperature
D. A windbvane is an instrument used in measuring wind direction.
During the formation of the sun, gravity pulled matter closer and closer
together until what event occurred?
A. Radioactive decay began.
B. Nuclear fusion reactions began.
C.Neutrons and protons formed.
D. A nebula exploded.
Answer:
c
Explanation:
cuz
How many moles are represented by 86.5 g of Ca(OH)2?
*please help fast*
Answer:
30 2 the second power
Explanation:
Calcium hydroxide, commonly known as hydrated lime or slaked lime, is a soft white powder that is used as a primary ingredient in the chemical industry.
What is Calcium Hydroxide?Its chemical formula is Ca(OH)2. When calcium oxide and water are combined, it produces.
There are two hydroxide ions (OH) in the molecule for every calcium ion (Ca2+). The substance is ionic, and both electrolytic and aqueous dissociations result in calcium and hydroxide ions.
When water is added to dry portland cement to create concrete, this reaction takes place, and the mixture warms up and releases heat. An alternative method of manufacturing entails an aqueous double displacement reaction between sodium hydroxide and calcium chloride.
Therefore, Calcium hydroxide, commonly known as hydrated lime or slaked lime, is a soft white powder that is used as a primary ingredient in the chemical industry.
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Tides are the result of forces exerted on Earth's oceans, mostly by which celestial body?
The Sun
Jupiter
The Moon
Venus
Answer:
Explanation:
The moon
Which One Is the Wrong One?
Answer:
I would say the second one it's the wrong
what is the molarity of a solution in which 10.0 g of AgNO3 is dissolved in 5 L of a solution
Answer:
no of moles = given mass/molar mass
no of moles = 10/169.87 =0.058moles
molarity = number of moles of solute/volume of solution in litre
molarity = 0.058/5
molarity = 0.0116
The level of mercury in a barometer falls as the air pressure falls.
True
False
Real answers only or you will be reported and banned from brainly
Answer:True
Explanation:
What is the volume of a gas if the gas has a volume of 100.0 L at 135 C. What is the volume of the gas if its temperature decreases to 72.0 C
Answer: The volume of gas is 84.6 L at [tex]72.6^0C[/tex]
Explanation:
To calculate the final volume of the system, we use the equation given by Charles' Law. This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.
Mathematically,
[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]
where,
[tex]V_1\text{ and }T_1[/tex] are the initial volume and temperature of the gas.
[tex]V_2\text{ and }T_2[/tex] are the final volume and temperature of the gas.
We are given:
[tex]V_1=100.0L\\T_1=135^oC=(135+273)K=408K\\V_2=?\\T_2=72.0^0C=(72.0+273)K=345K[/tex]
Putting values in above equation, we get:
[tex]\frac{100.0L}{408K}=\frac{V_2}{345K}\\\\V_2=84.6L[/tex]
Thus the volume of gas is 84.6 L at [tex]72.6^0C[/tex]
What force pulls the water down hill in a watershed, preventing it from going
OVER the drainage divide? *
Answer:
gravity
Explanation:
force downward due to gravity
Answer:
Gravity is the answer.
Color blindness is a sex-linked, _______ trait.
-recesive
-dominat
-multiple allele
-multiple dominance
Answer:
recessive trait
Answer:
recessive
Explanation:
Color blindness is a sex-linked, recessive trait.
hope this helps and is right :)
What does a base release when it is placed in water?
Select one:
a.Chloride ion (Cl-)
b.Hydronium ion (H3O+)
c.Calcium ion (Ca2+)
d.Hydroxide ion (OH-)
Answer:
D - Hydroxide Ion (OH-)
Explanation:
A base provides either hydroxide ions (OH–) or other negatively charged ions that combine with hydrogen ions, reducing their concentration in the solution and thereby raising the pH. In cases where the base releases hydroxide ions, these ions bind to free hydrogen ions, generating new water molecules.
You need 267 mL of .25M NaCl,
but the only supply of NaCl you
have
is 1.75M NaCl. How do you prepare
the required solution?
To prepare 267 mL of 0.25M NaCl, we need to take 38.29 mL of 1.75M NaCl solution and add water to it until it makes the final volume up to 267 mL.
We need to prepare the solution of 0.25 M NaCl using 1.75 M NaCl solution, we can use the dilution formula:
[tex]C_1V_1 = C_2V_2[/tex]
where [tex]C_1[/tex], [tex]V_1[/tex] is the concentration and the volume of the initial solution, [tex]C_2[/tex], [tex]V_2[/tex] is the concentration and the volume of the final solution.
We know the final concentration and the final volume that we are required to make. So we can use the above relation to find [tex]V_1[/tex] of the solution:
[tex]V_1 = (C_2 * V_2) / C_1[/tex]
Now after substituting the values in the relation, we get:
[tex]V_1 = (0.25 M x 267 mL) / 1.75 M\\V_1 = 0.03829 L or 38.29 mL[/tex]
So to prepare 267 mL of 0.25M NaCl, we need to take 38.29 mL of 1.75M NaCl solution and add water to it until it makes the final volume up to 267 mL.
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can any one solve this quiz plz
Answer:
1. It is stoichiometric.
2. O2 is the limiting reactant.
3. 9.0 g of C2H6 remain unreacted.
4. 17.6 g of CO2.
5. 85.2%.
Explanation:
Hello there!
In this case, for the given chemical reaction:
[tex]2C_2H_6+7O_2\rightarrow 4CO_2+6H_2O[/tex]
We can see that:
1. It is stoichiometric and is balanced because the reactants yields the products according to the law of conservation of mass.
2. In this part, it is possible to calculate the moles of ethane by using its molar mass:
[tex]n_{C_2H_6}=15g*\frac{1molC_2H_6}{30.08g} =0.50molC_2H_6[/tex]
And the moles of oxygen by knowing that one mole is contained in 22.4 L at STP:
[tex]n_{O_2}=\frac{1mol}{22.4L} *15.68L=0.7molO_2[/tex]
Thus, by calculating the moles of carbon dioxide product by each reactant, we can identify the limiting one:
[tex]n_{CO_2}^{by\ C_2H_6}=0.50molC_2H_6*\frac{4molCO_2}{2molC_2H_6} =1.0molCO_2\\\\n_{CO_2}^{by\ O_2}=0.70molO_2*\frac{4molCO_2}{7molO_2} =0.4molCO_2\\[/tex]
Thus, since oxygen yields the fewest moles of CO2 product, we infer it is the limiting reactant.
3. In this part, we calculate the mass of C2H6 that actually react first:
[tex]m_{C_2H_6}^{reacted}=0.4molCO_2*\frac{2molC_2H_6}{4molCO_2}*\frac{30.08gC_2H_6}{1molC_2H_6} =6.0gC_2H_6[/tex]
Thus, the leftover of ethane (C2H6) as the excess reactant is:
[tex]m_{C_2H_6 }^{leftover}=15g-6.0g=9.0g6.0C_2H_6[/tex]
4. Since 0.4 moles of carbon dioxide were produced, we use its molar mass to calculate the mass as its theoretical yield:
[tex]m_{O_2}^{theoretical}=0.4molCO_2*\frac{44gCO_2}{1molCO_2}=17.6gCO_2[/tex]
5. Finally, the percent yield is gotten by dividing the actual yield by the theoretical one:
[tex]Y=\frac{15g}{17.6}*100\%\\\\Y=85.2\%[/tex]
Best regards!
Copper extraction symbol equation
Answer:
Fe(s) + Cu2+(aq) ===> Fe2+(aq) + Cu(s)
Answer:
2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)
Explanation:
2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)
if people are blind can they dream
Answer:
yeah they dream in weird shapes mostly I think. unless they weren't born blind then they dream normally I think
Answer:
Kind of, our dreams refer to what we see, but blind people can't see, they might have dreams what the world might look like
The scientist who wrote the universal law of gravitation was
The scientist who wrote the universal law of gravitation was Sir Isaac Newton.
The scientist that wrote the universal law of gravitation was Isaac Newton.
What is the universal law of gravitation?The universal law of gravitation states that every object in this universe attracts every other object around it with a force, whose magnitude is directly proportional to the product of their masses and indirectly proportional to the square of the distance between them.
The universal law of gravitation was first published by the scientist Issac Newton in the year 1687.
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Someone help me please?
How can a chemical reaction be sped up? Select from the drop-down menu to correctly complete the statement. Add a Choose... that is unaffected by a reaction. the choices are, A: catalyst B: coefficient C: product
Answer:
A: catalyst
Explanation:
In Chemistry, the rate of reaction of chemical elements (reactants) can be sped to produce a chemical compound or elements (products), through the addition of a catalyst that is unaffected by the reaction.
This ultimately implies that, to speed up a chemical reaction, add a catalyst that is unaffected by a reaction.
For example, an enzyme refers to a biological catalyst that is typically used to speed up (accelerate) the rate of a chemical reaction by lowering the activation energy of its reactants.
An enzyme can be defined as a biological catalyst that typically lowers the activation energy of a biological reaction. When the activation energy of a reaction is low, the rate of the reaction would be faster. Therefore, an enzyme speeds or catalyzes the rate of a reaction by lowering its activation energy.
Generally, an increase in temperature increases or speeds up the rate of a reaction while low temperature limits or reduces the rate of a reaction. The optimal temperature for enzymes in the human body is around 37 degrees celsius.
Contains a nonmetal and metal
A) base
B) acid
C) covalent bond
D) salt