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]
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.
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!
What dose the T-cell attack
Answer:
killer T-cell find and destroy infected cells that have been turned into virus-making factories
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.
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
True/False: A virus could have a mutation that makes it more transmissible (higher
chance of spreading).
Answer True
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.
True or False: If bubbles are produced when two reactants are mixed, a chemical reaction has occurred.
Answer:
True
Explanation:
Because yes
Answer:
true because that is a reactant or the chemical
Explanation:
Explain why the following are made of thermosetting plastics.
(a) Saucepan handles
(b) Electric plugs/switches/plug boards
Answer:
a: they're used in saucepan handles 'cause they don't soften when heated and also 'cause they cant be bent easily.
b: thermosetting plastics are bad electricity conductors. they don't get moulded and are also hard and strong.
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:
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)
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]
______________________________ is the attraction amongst molecules that are dissimilar.
A.) Transpiration
B.) Cohesion
C.) Adhesion
D.) Polarity
Answer:
ily
Explanation:
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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Contains a nonmetal and metal
A) base
B) acid
C) covalent bond
D) salt
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
help please and show work!
Answer:
Mg + 2HCl → MgCl2 + H2
Explanation:
Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2
Calcium hydroxide, Ca(OH)2, is an ionic compound with a solubility product constant, Ksp, of 6.5×10–6. Calculate the solubility of this compound in pure water.
Answer: The solubility of this compound in pure water is 0.012 M
Explanation:
Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as [tex]K_{sp}[/tex]
The equation for the ionization of the is given as:
[tex]Ca(OH)_2\rightarrow Ca^{2+}+2OH^-[/tex]
By stoichiometry of the reaction:
1 mole of [tex]Ca(OH)_2[/tex] gives 1 mole of [tex]Ca^{2+}[/tex] and 2 mole of [tex]OH^-[/tex]
When the solubility of [tex]Ca(OH)_2[/tex] is S moles/liter, then the solubility of [tex]Ca^{2+}[/tex] will be S moles\liter and solubility of [tex]OH^-[/tex] will be 2S moles/liter.
[tex]K_{sp}=[Ca^{2+}][OH^{-}]^2[/tex]
[tex]6.5\times 10^{-6}=[S][2S]^2[/tex]
[tex]S=0.012M[/tex]
Thus solubility of this compound in pure water is 0.012 M
Which One Is the Wrong One?
Answer:
I would say the second one it's the wrong
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.
How many molecules of nitrogen gas are found in 0.045 L of nitrogen gas at STP
Answer:
1.2 × 10²¹ molecules
Explanation:
Step 1: Given data
Volume of nitrogen gas (V): 0.045 LConditions: Standard temperature (273.15 K) and standard pressure (1 atm)Step 2: Calculate the number of moles corresponding to 0.045 L of nitrogen gas at STP
At STP, 1 mole of nitrogen gas occupies 22.4 L.
0.045 L × 1 mol/22.4 L = 2.0 × 10⁻³ mol
Step 3: Calculate the number of molecules in 2.0 × 10⁻³ moles of nitrogen
We will use Avogadro's number: there are 6.02 × 10²³ molecules in 1 mole of molecules of nitrogen gas.
2.0 × 10⁻³ mol × 6.02 × 10²³ molecules/1 mol = 1.2 × 10²¹ molecules
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:
Can someone help me please I am doing a test!!.
Your lips are more sensitive to touch than your forehead. What is different about the touch receptive fields in the lips compared to the forehead?
(Mark the one best answer.)
A There are more touch receptive fields in the lips.
B The touch receptive fields are bigger in the lips.
C The touch receptive fields are more sensitive in the lips.
D The touch receptive fields are used more often in the lips
Answer:
c i think
Explanation:
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 :)
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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Please help me, I really don't want to fail but I don't know how to do this
Answer:
A)
4, 7, 4, 6
B)
12 moles
Explanation:
[tex] NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)[/tex]
__↑______↑
8.00 mol | 14.00 mol
________________
[tex] NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)[/tex]
You can turn this into a system of variables which are solvable.
To do this, create variables for the coefficients of each compound in the reaction respectively.
[tex] a(NH_{3}(g)) + b(O_{2}(g)) → \\c(NO_{2}) + d(H_{2}O(g))[/tex]
Because to be balanced, the count of atoms in each element of the compound correspond to the coefficient of the variable in that compound so that the count of the left (reactant) side is set equal to the right (product) side.
a corresponds to the coefficient of the first compound, b corresponds to the coefficient of the second compound, c corresponds to the coefficient of the third compound, and d corresponds to the coefficient of the fourth compound.
(Reactant = Product)
Reactant: 1a [N] Product: 1c.
Reactant: 3a [H] Product: 2d.
Reactant: 2b [O] Product: 2c + 1d.
Thus the system is:
1a = 1c
3a = 2d
2b = 2c + 1d.
Then just use the substitution methods to solve.
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:
What type of reaction is
illustrated?
Ca + CuSO4 -> CaSO4 + Cu
A. synthesis
B. decomposition
C. single
replacement