Answer:
The answer is C.They follow a pattern for valence electrons.
Explanation:
I did A P E X quiz.
The elements in the tall columns of the periodic table called "representative elements" because they follow a pattern for valence electrons. Therefore option C is correct.
The tall columns in the periodic table are known as groups or families. The elements within each group exhibit similar chemical behavior and share certain characteristics.
The elements in these groups are often referred to as "representative elements" because they represent or exemplify the general properties and trends of their respective groups. One of the key patterns observed among the representative elements is their valence electrons.
In the representative elements, the number of valence electrons follows a predictable pattern within each group.
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pls help!! A 24.0 mL sample of HNO3 is neutralized by 32.1 mL of 0.150 M KOH. What is the molarity of HNO3? Report your answer with 3 significant figures.
Answer:
O.2006 M
Explanation:
M1V1 =M2V2
M1 = M2V2/V1 =0.150M*32.1 ml/24.0 ml = 0.2006 M
what causes the volume to change in gases? (choose all that apply)
a) temperature
b) density
c) shape of container
d) pressure
Answer:
Temperature, pressure, shape of container
Answer:
temperature, density, pressure.
Explanation:
Will give BRAINLIEST: Is a new theory of light and matter needed to explain what happens at very high energies and temperatures?
Explanation:
All of that visible trail of radiation, especially in the form of gamma rays—the extremely energetic cousins of ordinary light. Astronomers have known for three decades that brilliant flashes of these rays, called gamma-ray bursts, arrive daily from random directions in the sky. Recently astronomers have pinned down the location of the bursts and tentatively identified them as massive supernova explosions and neutron stars colliding both with themselves and black holes. But even now nobody knows much about what goes on when so much energy is flying around. Matter grows so hot that it interacts with radiation in unfamiliar ways, and photons of radiation can crash into each other and create new matter. The distinction between matter and energy grows blurry. Throw in the added factor of magnetism, and physicists can make only rough guesses about what happens in these hellish settings. Perhaps current theories simply aren’t adequate to explain them.
An apple in a tree has a gravitational store of 8J. As it falls, it accelerates constantly until it hits the ground. What is the apple's maximum kinetic store?
Answer:
8J
Explanation:
From the question, the gravitational stored energy is 8J.
So Mgh=8J.
The kinetic energy is ?
When we use the law of conservation of energy, as the apple is moving and about to it the ground, it has 0m speed.
Which means that the potential energy at rest i.e when the apple is on the ground is zero. When the apple is getting to the ground, KE +PE is conserves.
At the top of the tree, the Apple has zero potential energy because velocity is zero at rest and on hitting the ground, the apple has kinetic energy.
So, the maximum Kinetic energy is 8J.
Write the balanced equation for the reaction between HCl and NaOH. Then, calculate the molarity of the NaOH.
Answer:
HCl (aq) + NaOH (aq) --> H2O (L) + NaCl (aq)
Explanation:
HCl is a strong acid while NaOH is a strong alkali. Hence both should dissociate completely in water and 1 mol of HCl will fully neutralise 1 mol of NaOH.
I'm assuming that Part 2 on molarity is part of a data based question that requires you to calculate the number of moles of NaOH based on the data provided and the equation that you are required to balance. Hence, I can't help you with it as I do not have the values.
A compound, X contains 92.31 % C and 7.69 % H.
RMM of X is 78. Determine the molecular formula.
Answer:
C6H6
Explanation:
Just use the table method to find the ratio of C to H and then compare the RMM with that of the empirical formula.
Answer:
C6H6
Explanation:
We divide each percentage by the relative atomic mass of the element:
Carbon: 92.31 / 12.011 = 7.68
Hydrogen: 7.69 / 1.008 = 7.63
So the ratio of carbon to hydrogen is 1:1.
Empirical formula is CH - which has a MM of 13.019
The RMM is 78 so the molecular formula = 78/13.019 = 6 * CH
So it is C6H6 (Benzene).
24-Complete the following sentence:
Osmosis is a process during the _____ moves to balance the concentrations on both sides of a membrane.
the choices:
a: solute
b: solvent
c: substrate
d: soda cracker
Answer:
B. Solvent
Explanation:
In osmosis, water always moves from low solute concentration to high solute concentration. SOLUTE NEVER MOVES AS IT CANNOT PASS THE SELECTIVELY PERMEABLE MEMBRANE. alot of caps but need to stress this concept cuz otherwise this concept gets very confusing
The specific heat of ethanol is 2.44 J/g ֯C. How many kJ of energy are required to heat 50.0 grams of ethanol from -20 ֯C to 68 ֯C? (heat equation)
Answer:
Heat energy required (Q) = 10.736 KJ
Explanation:
Given:
Specific heat of ethanol (C) = 2.44 J/g °C
Mass of ethanol (M) = 50 gram
Initial temperature (T1) = -20°C
Final temperature (T1) = 68°C
Find:
Heat energy required (Q) = ?
Computation:
Change in temperature (ΔT) = 68°C - (-20°C)
Change in temperature (ΔT) = 88°C
Heat energy required (Q) = mC(ΔT)
Heat energy required (Q) = (50)(2.44)(88)
Heat energy required (Q) = 10,736 J
Heat energy required (Q) = 10.736 KJ
The stock solution of hydrochloric acid is 12.0M HCI. If the teacher starts with 130 ml of this concentrated acid, what volume of 3.0M HCI can be prepared?
Answer:
520mL
Explanation:
Data obtained from the question include:
Molarity of stock solution (M1) = 12M
Volume of stock solution (V1) = 130mL
Molarity of diluted solution (M2) = 3M
Volume of diluted (V2) =..?
The volume of the diluted solution can be obtained as follow:
M1V1 = M2V2
12 x 130 = 3 x V2
Divide both side by 3
V2 = 12 x 130 / 3
V2 = 520mL.
Therefore, 520mL of the diluted solution can be prepared.
How many oxide ions are in 0.55 grams of titanium oxide?
Answer: There are [tex]0.052\times 10^{23}[/tex] oxide ions
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}=\frac{0.55gg}{64g/mol}=0.0086moles[/tex]
1 mole of TiO contains = [tex]6.023\times 10^{23}[/tex] oxide ions
Thus 0.0086 moles of TiO contains = [tex]\frac{6.023\times 10^{23}}{1}\times 0.0086=0.052\times 10^{23}[/tex] oxide ions
There are [tex]0.052\times 10^{23}[/tex] oxide ions
Which statement about the extraction of metals is correct? *
A. Aluminium is extracted from bauxite by electrolysis.
B. Aluminium is extracted from hematite by heating with carbon.
C. Iron is extracted from bauxite by heating with carbon.
D. Iron is extracted from hematite by electrolysis.
Answer:
Explanation:
In this reaction, the iron(III) oxide is reduced. to iron, and the carbon is oxidised. to carbon dioxide. In the blast furnace, it is so hot that carbon monoxide can be ...
The statement about the extraction of metals that is correct is Aluminium is extracted from bauxite by electrolysis.
What is extraction of metals?Extraction of metals refers to various methods use to extract metals from the ground and refining it to a form that will easily be use by man.
Therefore, The statement about the extraction of metals that is correct is Aluminium is extracted from bauxite by electrolysis.
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A gas with a volume of 15L at 640K is cooled at a constant pressure until the volume reaches 5L. What is the new temperature?
Answer:
The new temperature is 213.33 K
Explanation:
Charles's law indicates that the volume of gas at constant pressure is directly proportional to its temperature. This law indicates that if the temperature increases the volume increases and if the temperature decreases the volume decreases.
So, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the ratio between volume and temperature will always have the same value:
[tex]\frac{V}{T}=k[/tex]
When you want to study two different states, an initial and a final one of a gas, the expression can be applied:
[tex]\frac{V1}{T1} =\frac{V2}{T2}[/tex]
In this case, you know:
V1= 15 LT1= 640 KV2= 5 LT2=?Replacing:
[tex]\frac{15 L}{640 K} =\frac{5 L}{T2}[/tex]
Solving:
[tex]T2=\frac{5 L}{\frac{15 L}{640 K} }=\frac{5 L*640 K}{15 L}[/tex]
T2= 213.33 K
The new temperature is 213.33 K
Which table correctly describes the uses of aldehydes?
table A
table B
table C
table D
Answer:
Correct answer is table A i might be wrong
Answer:
It's A - table A
Explanation:
On Edge 2021
Explain why your hair sticks to a plastic (polyethylene) comb.
Answer:
Due to the accumulation of static charges/due to static electricity
Joel weighs a basket containing 7 peaches.
Each peach weigh 200g. How many kilograms does the basket weigh
Answer:
Explanation:
7 times 200 is 1400 grams but thats not the question it asks in kilo's so i got a converter and the correct answer is 1.4 kilograms
Have a nice day :)
please give me brainiest lol
Answer:
Explanation:
1 kg is 1000 grams
1 peach is 200 grams
7 peaches are 200*7 = 1400 grams
Therefore the number of kg = 1400 grams // 1000 grams /kg
The number of kg = 1.4 kg.
Why are some areas rich in certain resources, while other areas don’t seem to have any natural resources
Answer:
The geographical occurrence or spatial distribution of earthly resources made them abundant at some place and lacks at other.
Explanation:
Low latitudes regions receive more energy and plenty of rainfall from the sun, while higher latitudes obtain less energy from the sun and little rainfall. Metallic minerals are easily available in regions with strong tectonic activity, and fossil fuels are found in sedimentary rocks. The plains deliver flat landscapes and rich soil which is ideal for growing crops, on the other hand, steep hills and dry areas are more difficult for the activity. Therefore climate and geography play a vital role in the uneven distribution of natural resources across the globe.
What happens when a piece of Mg ribbon is burnt? Name the
new substance formed. Write a balanced chemical equation.
Answer:
When a Magnesium Ribbon is burnt, a powdery substance called magnesium oxide is formed.
Explanation:
There has obviously been a chemical change because several chemical properties of the magnesium have been modified: the color, the texture and the mass.
The increase in mass is due to the fact that oxygen from the air has combined with the magnesium to make magnesium oxide, MgO.
The chemical equation, Mg + O2 MgO shows this reaction but it needs to be balanced to make 2Mg + O2 2MgO.
Using stoichiometry, we can convert this eqation into an equation with moles:
2 mol Mg + 1 mol O2 2 mol MgO.
Next, we convert to grams using atomic masses obtained from the periodic table:
48g Mg + 32g O2 80g MgO
Lastly, we determine the same thing in the proportions we used. In other words, we used only 0.15g of Mg (not 48g) so everything needs to be divided by 320. So 80 / 320 = 0.25 g. If we burn 0.15 g of Mg, we obtain 0.25 g of MgO.
Hope this helps!!!
This is my first answer.
i don’t know the answers to these pls help
Answer:
4. Option C. Pentane.
5. Option D.
Explanation:
4. Hydrocarbons are compound containing carbon and hydrogen only. Hydrocarbons are said to be saturated when they contain only carbon to carbon single bond. All alkanes are saturated hydrocarbon.
The correct answer is pentane.
5. Isomerism is the phenomenon whereby two or more compounds have the same molecular formula but different structural patterns. The compounds involved are called isomers.
A careful observation of the diagram above shows that only option D satisfied the definition of Isomerism as the two compound both have the same molecular formula as C3H8O but different structural patterns.
Note: option C does not contain isomers as Isomerism can not occur in a compound having just 1 carbon atom.
Que tienen en comun el chocolate, las papas fritas y la hamburguesa?
Que tienen en comun los vegetales, el huevo y el pan?
Answer: todos terminan en tu boca
Explanation:
Hahaha
Consider the unit cell of aluminum with aluminum ion on every corner and every face-centered site of the cube.
Question
1. Using the value of ionic radius of aluminum ion r=0.143 nm, the length of each edge of the unit cell can be calculated as what nm?
2.Using atomic weight value of aluminum 27.0, the density of aluminum can be calculated as what g/cm^3
Answer:
1) 0.4045nm
2) 0.0027096117g/cm³
Explanation:
1) Using the value of ionic radius of aluminum ion r=0.143 nm, the length of each edge of the unit cell can be calculated as what nm?
In the question above, using a face centered cubic structure, we have:
For a face centered site of the cube,
The diagonal = 4r
Where r =Atomic or ionic radius of Aluminum
Let the edge length of the cube be represented by X
Therefore, we have based on Pythagoras theorem,
X² + X² = (4r)²
2X² = 16r²
Divide both sides by 2
X² = 8r²
Find the square root of both sides
X = √8 × r
Since r = 0.143nm
The length of each edge of the unit cell can be calculated as
X = √8 × 0.143nm
X = 0.4044650788nm
Approximately = 0.4045nm
2) Using atomic weight value of aluminum 27.0, the density of aluminum can be calculated as what g/cm^3
Density of an object = Mass of the Object / Volume of the Object.
The object in this question = Cube
Step 1
Volume of a cube = (Length of the cube)³
In the question above, side length of the cube = 0.4045nm
When would convert 0.4045nm to centimeters
= 1 nm = 1 × 10^-7 cm
0.4045nm =
Cross multiply
= 4.045 × 10^-7 cm
Volume of the Aluminum cube =(4.045 × 10^-7cm)³
= 6.618439112 ×10^-20cm³
Step 2
The atomic weight value of aluminum is given as 27.0 in the question
A face centered cubic structure has 4 atoms per unit cell.
1 Atomic mass or weight value = 1.6605 × 10^-24 grams
Hence, the mass of Aluminum is calculated as:
(4 atoms /1 cell )× 1 unit × (27/ 1 atom of Aluminium) × (1.6605 × 10^-24g/ 1 Atomic mass value)
= 1.79334 ×10^-22g
Density = Mass/Volume
= 1.79334 ×10^ -22g /6.618439112 ×10^-20cm³
= 0.0027096117g/cm³
Isotopes:
A. of a given element have different numbers of neutrons
B. are atoms that have gained or lost electrons
C. of a given element have equal numbers of neutrons
D. of a given element have equal numbers of protons and neutrons
E. are atoms of different elements which have the same mass
Answer:
a
Explanation:
Which set of characteristics would you use to classify this planet as an inner or terrestrial planet?
Answer:
Dense and solid. And located near a star.
Explanation:
The set of characteristics that you would use to classify this planet as an inner or terrestrial planet is Dense and solid.
What are the characteristics used to classify terrestrial planets?Terrestrial planets are Earth-like planets made of rocks or metals with a hard floor. Terrestrial planets even have a molten heavy-steel middle, few moons, and topological capabilities which include valleys, volcanoes, and craters.
Which set of traits describe the internal planets?
All are solid, dense, and rocky. not one of the internal planets has rings. compared to the outer planets, the internal planets are small. they have shorter orbits across the sun and they spin more slowly.
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Which of these compounds is the odd
one out? *
(1 Point)
H2O
NaBr
NH₃
HCI
PLEASE ANSWER ASAP!!! What are examples of Exothermic or Endothermic processes found at home?
Answer:
Explanation:
Example for Endothermic include melting ice cubes, cooking eggs, or baking breads.
Example for Exothermic include Burning candles, lighting match, or hot packs
How many grams of krypton gas would occupy 1.34L at STP?
Answer:
5.01 g
Explanation:
At STP means at standard temperature and pressure, this is when the pressure is at 1 atm and temperature is at 273 K. At this point, the volume is 22.4 L for 1 mole of any ideal gas at a temperature equal to 273.15 K and a pressure equal to 1.00 atm
The molar mass of krypton as gotten from the periodic table is 83.8 g/mol. At STP, an ideal gas occupies 22.4 L/mol. Therefore, the grams that 1.3 L of krypton gas would occupy is:
[tex]mass=\frac{1mol}{22.4L} *\frac{83.8g}{1mol} *1.34L=5.01g[/tex]
Bleach is a 0.750 M solution of sodium hypochlorite. What volume, in litres, would contain 120.3 g of sodium hypochlorite?
Answer:
2.15 L
Explanation:
M(NaOCl) = 23.0 + 16.0 + 35.5 = 74.5 g/mol
120.3 g *1 mol/74.5 g = 1.615 mol NaOCl
0.750 M = 0.750 mol/L
1.615 mol * 1L/0.750 mol = 2.15 L
In a solution of brine (salt water), what is the salt? A. a solute B. a solvent C. a solution D. a reactant E. a product
Answer:
solute
Explanation:
solvent is the water solution is the whole mixture product is the solution
A. a solute
B. a solvent
C. a solution
D. a reactant
E. a product
P O R F A V O R
4. Expresa las siguientes magnitudes en unidades del Sistema
Internacional. (1 punto)
a. 45 m3
b. 1250 cm3
c. 63 días
d. 97 cm/min2
e. 927 g∙cm/min2
f. 97 km/h2
g. 2500 g/cm2
h. 36 km/h
Answer:
a. 45×10³ kg
b. 1.25 kg
c. 5443200 s
d. 2.69×10⁻⁴ m/s²
e. 2.57×10⁻⁶N
f. 7.48×10⁻³ m /s²
g. 2.45 Pa
h. 10 m/s
Explanation:
The SI units are: kg, m, s, N, K, A, Pa, J and cd
a. 1 g is the mass for 1 cm³. We convert the m³ to cm³
45 m³. 1×10⁶ cm³ / 1 m³ = 45×10⁶ cm³
By the way, 45×10⁶ cm³ = 45×10⁶ g
We convert the g to kg → 45×10⁶ g . 1 kg / 1000 g = 45×10³ kg
b. As 1 g = 1 cm³, we convert the cm³ to g and then, the g to kg
1250 cm³ = 1250 g → 1250 g . 1kg / 1000 g = 1.25 kg
c. 1 day has 24 hours; 1 hour has 60 minutes; 1 minute has 60 seconds
1 hour has 3600 s. Then 24 h . 3600 s / 1 h = 86400 s
86400 s/d. 63 d = 5443200 s
d. 1 min² = 3600 s²
97 cm / 3600 s² = 0.0269 cm/s² / 100 = 2.69×10⁻⁴ m/s²
e. 927 g.cm / min² / 3600 s² = 0.2575 g.cm/s² → dyn
We need to convert dyn to N
1 dyn = 10⁻⁵N → 0.2575 dyn . 10⁻⁵N / 1dyn = 2.57×10⁻⁶N
f. 1 m/s² = 12960 km/h²
12960 km/h² . 1 m/s² / 97 km/h² = 7.48×10⁻³ m /s²
g. 2500 g/cm² . 1kg / 1000 g = 2.5 kg/cm²
1 Pa = 1.02kg/cm²
2.5 kg/cm² . 1 Pa / 1.02 kg/cm² = 2.45 Pa
h. 1 h = 3600 s
36 km / 3600 s = 0.01 km /s → 0.01 km . 1000 m / 1 km = 10
= 10 m/s
8. What are two physical changes that cooling a hot substance may result in?
Answer:
Explanation:
Two possible changes are
a phase change. If water is presented in the form of steam, it may change into liquid, or eventually into a solid. While in a phase change, the temperature might change.a temperature change. Water at 65o what cooled can go down to 5o. There is no phase change, but there is a temperature change.Calculate the amount of energy required to boil 25.00 g of mercury.
Answer:
C. 7.4 kJ
Explanation:
Let assume that Mercury is at room temperature (25 °C). The energy required to boil the sample of mercury is the sum of sensible and latent heats. Mercury has a fussion and boiling points of -38.83 °C and 356.7 °C, respectively, and a specific heat of [tex]138\,\frac{J}{kg\cdot ^{\circ}C}[/tex]. Then:
[tex]Q = (25\,g)\cdot \left[\left(0.138\,\frac{J}{g\cdot ^{\circ}C} \right)\cdot (356.7^{\circ}C - 25^{\circ}C) + 296\,\frac{J}{g} \right][/tex]
[tex]Q = 8544.365\,J[/tex]
The option that offers the best approximation to the result is C.
