Which of the following are true about both the sun and the stars? Choose the three correct answers.
A.
Both are visible during the day in summer.
B.
Both move across the sky from east to west.
C.
Both change positions in the sky due to Earth's revolution.
D.
Both are visible at night in winter.
E.
Both appear in different positions in the sky due to Earth's rotation.
F.
Both move from north to south in the sky.
Answer:
D, F
Explanation:
Itis usually alloyed with aluminum to produce high quality, anti-corrosion
wheel mags
Answer:
Aluminum is the second most abundant metallic element on earth. It has been estimated that 8% of the earth's crust is composed of aluminum, usually found in the bauxite form. On a volume basis, aluminum has become the most widely used non-ferrous metal.
Primary aluminum production is the quantity of primary aluminum produced in a specified period and the quantity of molten or liquid metal tapped from pots that is weighed before transfer to a holding furnace or before further processing.
Explanation:
Car manufacturers use radiation for which task?
A) Sealing Windows
B) Drying paint
C) Cleaning tires
D) Lubricating engines
THE CORRECT ANSWER IS B.
#edge2021
Answer:
Indeed it is B, you are correct! :3
Explanation:
:3
Answer:
B. Drying paint
Car manufacturers use UV radiation to dry the paint o the vehicle. The high reflectivity of infrared radiation helps to keep the car interior cool. It also gives advantages over convection heating.
Explanation:
Hope it helps
Fill in the Blank
All three types of rock form in which earth layer? _________.
A reversible change, where appearance is altered, but the composition stays the same is _________. An irreversible change that alters the chemical makeup of a substance is _________. Is the melting of ice into liquid water a physical or chemical change? _____ What is involved in any change in matter? ________
The lithosphere is where all three forms of rocks form. A physical change is a reversible change and chemical changes are irreversible. The melting of ice is a physical change and change of matter is chemical.
What are physical and chemical changes. ?The lithosphere is the layer of earth where all three types of rocks such as igneous, metamorphic, and sedimentary can be found. The physical changes are those that affect physical properties and are reversible like heating and cooling.
While the chemical changes are irreversible. The physical changes lead to the change in form of the substance while chemical change leads to the rearrange of matter.
Find out more information about the types of rocks.
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The number of electrons in the valence shell of aluminum is
Answer: It has 13 electrons total and and 3 in the valance shell.
Explanation: Aluminum
Explain why this substance is formed?
if the temperature of 20.0 L of gas were increased to twice the initial value, while the pressure is held constant what would be the volume of the gas at the new temperature
Answer:
40 L
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 20 L
Initial temperature (T₁) = T
Final temperature (T₂) = 2T
Pressure (P) = constant
Final volume (V₂) =?
The new (i.e final) volume of the gas can be obtained as follow:
V₁/T₁ = V₂/T₂
20/T = V₂/2T
Cross multiply
T × V₂ = 20 × 2T
T × V₂ = 40T
Divide both side by T
V₂ = 40T /T
V₂ = 40 L
Therefore, the new volume of the gas is 40 L
Which of the following leads to a higher rate of effusion?
Answers:
1. Reduced temperature
2. Lower molar mass
3. Slower particle movement
4. Cooler gas sample
Answer:
Lower molar mass :)
Explanation:
Answer:
2. Lower Molar Mass
Explanation:
effusion can increase with either temperature increase, faster moving particles, or when the gas has lower molar mass. the only answer option that fits the description is answer option 2. Lower molar mass
Which of the following models a synthesis reaction?
Answer: D
Explanation: i’m right
10. Which best explains why the total mass of the product(s) would be less than the total weight of the
reactant(s) after a chemical reaction?
А
A physical change occurred.
B
Atoms involved in the reaction lost mass.
с
Precipitates were created in the new solution.
D
Gases were released to the atmosphere.
Answer:
D. Gases were released to the atmosphere
Explanation:
In accordance to the law of conservation of mass, the total amount of reactants must equate the total amount of products at the end of the reaction because matter can not be lost or created. However, certain changes like gas evolution, formation of precipitate etc. indicates the occurrence of a chemical reaction.
In a chemical reaction, the total mass of the product(s) would be less than the total weight of the reactant(s) because GASES, which constituted part of the mass of the reaction, WERE RELEASED INTO THE ATMOSPHERE. However, if the mass of the gas released can be accounted for, the amount of reactants and products must balance.
A paracetamol tablet was crushed and an excess of HCl 25cm³ of 1.0mol was added. the result of the solution was titrate against 0.5mol of NaOH. calculate the mass of CaCO3 in the paracetamol.
Answer:
1.35g of CaCO₃ are in the paracetamol
Explanation:
Assuming the volume of the 0.5mol NaOH was 23cm³
The CaCO₃ of paracetamol reacts with HCl as follows:
CaCO₃ + 2HCl → CO₂ + H₂O + CaCl₂
When an excess of HCl is added and titrated, we can find the moles of HCl that react = Moles CaCO₃ based on the second reaction:
NaOH + HCl → H₂O + NaCl
Moles added of NaOH:
23cm³ = 0.023L * (0.5mol / L) = 0.0115 moles NaOH = Moles HCl in excess
Moles of HCl:
25cm³ = 0.025L * (1.0mol / L) = 0.025 moles HCl
The moles of HCl that reacted = Moles CaCO₃ are:
0.025 moles - 0.115 moles = 0.0135 moles CaCO₃
The mass of CaCO₃ -Molar mass: 100.09g/mol- is:
0.0135 moles CaCO₃ * (100.09g/mol) =
1.35g of CaCO₃ are in the paracetamol__Zn + __HCl --> __ZnCl2 + __H2
If 26.22 Liters of Hydrogen gas are produced, how many moles of Hydrochloric acid were reacted?
Answer:
1. The balanced equation:
Zn + 2HCl —> ZnCl₂ + H₂
The coefficients are: 1, 2, 1, 1
2. 2.34 moles of HCl
Explanation:
1. The balanced equation
__Zn + __HCl —> __ZnCl₂ + __H₂
There are 2 atoms of H on the right side and 1 atom on the left side
It can be balance by writing 2 before HCl as shown below:
Zn + 2HCl —> ZnCl₂ + H₂
Now the equation is balanced.
The coefficients are: 1, 2, 1, 1
2. Determination of the number of mole of HCl that reacted.
NOTE: 1 mole of H₂ = 22.4 L at STP.
Zn + 2HCl —> ZnCl₂ + H₂
From the balanced equation above,
2 moles of HCl reacted to produce 1 mole (i.e 22.4 L) of H₂.
Finally, we shall determine the number of mole of HCl needed to produce 26.22 L of H₂. This can be obtained as follow:
From the balanced equation above,
2 moles of HCl reacted to produce 22.4 L of H₂.
Therefore, Xmol of HCl will react to produce 26.22 L of H₂ i.e
Xmol of HCl = (2 × 26.22)/22.4
Xmol of HCl = 2.34 moles
Thus, 2.34 moles of HCl is needed for the reaction.
an empty relative density bottle weights 20g. the bottle weights 40g when filled with petrol and 60g when filled with water. determine the density of the petrol.( density of water=1000kg/m³)
Answer:
500 Kg/m³
Explanation:
From the question given above, the following data were obtained:
Mass of empty bottle = 20 g
Mass of bottle + petrol = 40 g
Mass of bottle + water = 60 g
Density of water = 1000 Kg/m³
Density of petrol =?
Next, we shall determine the mass of water. This can be obtained as follow:
Mass of empty bottle = 20 g
Mass of bottle + water = 60 g
Mass of water =?
Mass of water = (Mass of bottle + water) – (Mass of empty bottle)
Mass of water = 60 – 20
Mass of water = 40 g
Converting 40 g to Kg, we have:
1000 g = 1 Kg
Therefore,
40 g = 40 × 1 Kg / 1000 g
40 g = 0.04 Kg
Next, we shall determine the volume of the bottle by calculating the volume of water. This can be obtained as follow:
Mass of water = 0.04 Kg
Density of water = 1000 Kg/m³
Volume of water =?
Density = mass / volume
1000 = 0.04 / volume
Cross multiply
1000 × volume = 0.04
Divide both side by 1000
Volume of water = 0.04 / 1000
Volume of water = 4×10¯⁵ m³
Thus, the volume of the bottle is 4×10¯⁵ m³
Next, we shall determine the mass of the petrol. This can be obtained as follow:
Mass of empty bottle = 20 g
Mass of bottle + petrol = 40 g
Mass of petrol =?
Mass of petrol = (Mass of bottle + petrol ) – (Mass of empty bottle)
Mass of petrol = 40 – 20
Mass of petrol = 20 g
Converting 20 g to Kg, we have:
1000 g = 1 Kg
Therefore,
20 g = 20 × 1 Kg / 1000 g
20 g = 0.02 Kg
Finally, we shall determine the density of the petrol. This can be obtained as follow:
Mass of petrol = 0.02 Kg
Volume of petrol = 4×10¯⁵ m³
Density of petrol =?
Density = mass / volume
Density of petrol = 0.02 / 4×10¯⁵
Density of petrol = 500 Kg/m³
5.14 x 1023 ions NaCl to Moles
Answer:
2 moles
Explanation:
For a mole NaCi, we have a mole of sodium ion and a mole of chloride.
Plants do not grow well when the soil is either too acidic or too basic. How do you solve these problems?
How many moles of O are in 11.6 mol Fe(NO3)3?
Express your answer in moles to three significant figures.
Answer:
Why might the expression "1 mole of nitrogen" be confusing? ... WebAssign will check your answer for the correct number of significant ... Calculate the moles of O atoms in 8.18 g of Mg(NO3)2. ... If the molar mass of hemoglobin is 6.8 104 g/mol, how many Fe2+ ions are ... (_) C7H16(l) + 11 O2(g) 7 CO2(g) + 8 H2O(g)
Explanation:
For number 2 I need help with balancing equations and list the type of reaction plz and thank you
Answer:
Cd(NO3)2 + FeCl3 = CdCl2 + Fe(NO3)2
is an impossible equation to balance as this reaction will simply not occur and it will not work either ways
did your teacher make this ?
Which statement about the atomic nucleus is correct?A.The nucleus is made of protons and has a negative charge.B.The nucleus is made of protons and neutrons and has a negative charge.C.The nucleus is made of electrons and has a negative charge.D.The nucleus is made of protons and neutrons and has a positive charge.
A sample of gas at 62.0°C occupies a volume of 4.80 L at a pressure of 2.90 atm. How many
moles of gas are contained in the sample?
Answer: 37.01 moles (mol) of gas
Explanation:Use PV=nRT
which is also equal to n=PV/RT
P=2.90
V= 4.80
R = 8.31 (R will always be the same in any equation)
T= 62.0
2.90 x 4.80= 13.92 / 8.31 x 62= 515.22
13.92/13.92=515.22/13.92
n= 37.01 mol
2. If 1.204 X 1024 atoms of sodium is 20% of the total sodium atoms in sodium
chloride NaCl), how many grams of salt do you have ?
Answer:
584.2 g
Explanation:
Hello there!
In this case, since we know the 20% of the atoms correspond to sodium, we can compute the total atoms as shown below:
[tex]\frac{1.204 x10^{24}}{0.2}=6.02x10^{24}atoms[/tex]
Which are also equal to 1 mol and the Avogadro's number of sodium chloride with a molar mass of 58.44 g/mol; thus, the grams of salt turn out to be:
[tex]6.02x10^{24}atoms*\frac{1mol}{6.022x10^{23}atoms} *\frac{58.44g}{1mol}\\\\=584.2g[/tex]
Best regards!
Suggest why sodium wasn’t produced until the early 19th century.
Answer:
The reason is that sodium attaches itself very strongly to other elements. Its compounds are very difficult to break apartand also because it is so reactive.
When these marbles collide, what force is experienced by each marble?
Answer:
when they collide they can experience collision
because without force collision wouldn't have happen.
24. What is the total number of grams of potassium chloride needed to saturate exactly 300 grams of water at 10°C?
1) 70 2) 90 3) 80 4) 60
Answer:
That would be 90 grams
Explanation:
This should be right but please, please, please correct me if I'm worng because I dont want anyone to fail because of me. Have a great day luv <3
The answer is option B , 90 grams of potassium chloride(KCl) is needed to saturate exactly 300 grams of water at 10°C
How do you define Solubility ?The measure of the degree to which a substance gets dissolved in a solvent to become a solution.
The solubility of KCl in water at 10°C is 31.2gm/100gm of water .
So in 300 gm of water 3 * 31.2 gm = 93.6 gm
Using Significant Figures we can select option B i.e. 90 gm.
Hence Option B , 90 grams of potassium chloride is needed to saturate exactly 300 grams of water at 10°C
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The radius of a spherical aluminum atom is 140 picometers. How many aluminum atoms could be lined up across a length of 27.9 cm.
Answer:
9.96 × 10⁸
Explanation:
Step 1: Calculate the diameter of 1 aluminum atom
The diameter of a sphere is 2 times the radius.
d = 2 × 140 pm = 280 pm
Step 2: Convert "d" to m
We will use the conversion factor 1 m = 10¹² pm.
280 pm × 1 m/10¹² pm = 2.80 × 10⁻¹⁰ m
Step 3: Convert the total length (L) to m
We will use the conversion factor 1 m = 100 cm.
27.9 cm × 1 m/100 cm = 0.279 m
Step 4: Calculate the number of atoms of aluminum required
We will use the following expression.
L/d = 0.279 m/2.80 × 10⁻¹⁰ m = 9.96 × 10⁸
Which of the statements listed below is negative aspect of a volcanic eruption?
A. generating geothermal energy.
B. lava flows and lahars clear areas of woodland or agriculture,
C. the dramatic scenery created by volcanic eruptions attracts tourist.
D. lava and ash deposited during a volcanic eruption breaks down to provide valuable
nutrients for the soil.
CANO
Answer:
C . the dramatic scenery created by volcanic eruptions attracts tourists.
The statement 'lava flows and lahars clear areas of woodland or agriculture' is a negative aspect of a volcanic eruption (Option B).
A volcanic eruption refers to the expulsion of lava and dangerous gases from a volcano.These volcanic eruptions can destroy large areas including lands for agriculture or woodland.A lahar can be defined as a mix of cold/warm water and fragments of sediments (rocks) that flow fast down the slope of the volcano.In conclusion, the statement 'lava flows and lahars clear areas of woodland or agriculture' is a negative aspect of a volcanic eruption (Option B).
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Which statement best describes the use of a chemical indicator in a titration?
A. It must be measured to the nearest 0.01 mL.
B. It must be colored in the acid solution.
C. It must measure pH directly at all pH values.
D. It must change color near the equivalence point.
The statement best describes the use of a chemical indicator in a titration is it must change color near the equivalence point.
What is a chemical indicator?A chemical indicator is any substance that shows a chemical change by color or other things.
In titration, phenolphthalein is used as an indicator in the titration of an acid or base.
Other chemical indicators are methyl yellow, litmus paper, and pH indicator.
Thus, the correct option is D. It must change color near the equivalence point.
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Which of the following characterizes a reaction at equilibrium?
A. The forward reaction stops, and the backward reaction starts.
B. The forward and backward reactions are equal.
C. The forward and backward reactions stop happening.
D. The reactants are changed into products.
SUBMIT
B. The forwards and backwards motions are equal
At chemical equilibrium,the forward and backward reactions are equal and opposite.
What is chemical equilibrium?Chemical equilibrium is defined as the condition which arises during the course of a reversible chemical reaction with no net change in amount of reactants and products.A reversible chemical reaction is the one wherein the products as soon as they are formed react together to produce back the reactants.
At equilibrium, the two opposing reactions which take place take place at equal rates and there is no net change in amount of the substances which are involved in the chemical reaction.At equilibrium, the reaction is considered to be complete . Conditions which are required for equilibrium are given by quantitative formulation.
Factors which affect chemical equilibrium are change in concentration , change in pressure and temperature and presence of catalyst.
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PLZ HELP I NEED THIS RN!
when the balls reach the bottom of the ramp, which statement will describe their energy?
A. they will have no kinetic energy
B. they will have 100% potential energy
C. they will have 100% kinetic energy
C. they will have different amounts of potential energy
Answer:
they will have 100% kinetic energy
Explanation:
all the potential energy has been used when it is at the bottom of the ramp
3)
Acid and Base Characteristics
Substance A
Substance
Substance D
Sour taste
Neutral taste
Substance B
Bitter taste
Strongly conducts
electricity
Strongly conducts electricity,
Sharp taste
Strongly conducts
electricity
Reacts with most metals to generate
hydrogen gas.
Weakly conducts
electricity
Can react with acids or
bases
Can react to make soap.
Generally will not react,
Predict which substance would not act as an acid or a base according to Bronsted-Lowry s definition
-)
alc
NH
A)
А
hing
Cale
8
B
Answer:C
Explanation:
Answer:
Substance D
Explanation:
USA Test Prep Corrections
Which one of the following atoms has the largest radius?
Sr, Rb, K, Ca, Y
Answer: Rb (rubidium) has a radius of 290 pm, making it have the largest of the 5 elements listed.
Explanation: