Answer:
i dont no this one plz the question is hard
Which sentence describes existing cells?
All cells, once formed, continue to live forever.
All cells come from previously existing cells.
All the cells that are on Earth have always been here.
All cells develop from the remains of other cells.
the element of group 1 are reactive but those of group 18 are inert, why
Answer:
Because elements of group 1 does not have stable electronic configuration and elements of group 18 have stable electronic configuration.
Explanation:
Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.
What are the element of group 1?Group 1 elements contain the alkali metals, Li, Na, K, Rb, Cs, and Fr. The alkali metals exist all soft, shiny, and metallic when cut. They react efficiently with water, have low melting points and densities, and are good conductors of electricity. They all include one valence electron that they lose easily to form ions. Noble gas exists as any of the seven chemical elements that create up Group 18 (VIIIa) of the periodic table. The elements exist as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).
The element of group 1 exist as reactive but those of group 18 exist as inert Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.
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If 16.4 grams of calcium nitrate is heated as shown in the reaction:
2Ca(NO3)2 -> 2CaO + 4NO2 + O2.
Calculate the volume of nitrogen dioxide produced at STP.
Answer:
7.2
Explanation:
you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios
number of moles of calcium nitrate=mass/mm
=16.4/102
=0.16g/mol
then you use the mole to mole ratios
2 : 4
0.16: x
2x/2=0.64/2
x=0.32g/moles of nitrogen dioxide
then you use the formula for the volume
v=22.4n
=22.4×0.32
=7.2
I hope this helps
Answer: Freezing point depression
Explanation:
freezing point depression is a phenomenon that describes why adding a solute or solvent results in the lowering of the freezing point of the solvent
What is the concentration of a solution formed by diluting 25.0 ml of a 3.8M glucose solution to 250ml
Explanation : số mol glucose 3.8M là :
n = Cm . V = 3.8 . 25 =95
=> Cm khi pha loãng = [tex]\frac{n}{V}[/tex] = [tex]\frac{95}{250}[/tex] = 0.38M
According to molar concentration, the concentration of a solution formed by diluting 25.0 ml of a 3.8 M glucose solution to 250 ml is 0.38 M.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.In case of 2 solutions given it is calculated as M₁V₁=M₂V₂,on substitution, M₂=3.8×25/250=0.38 M.
Thus, the concentration of a solution formed by diluting 25.0 ml of a 3.8 M glucose solution to 250 ml is 0.38 M.
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how can we separate the sugar from sugar solution
50. Carbon mono-oxide can be prepared by heating following substance with Conc. H2SO4. a. Oxalic acid b. Acetic acid c. Ethanoic acid d. All ic 252
A
Carbon monoxide gas can be prepared in lab by heating formic acid or oxalic acid with conc. H2SO4.
Procedure: Small amount of oxalic acid crystal is taken in a round- bottomed flask and all the apparatus are fitted as shown in figure. When conc. H2SO4 is poured in the flask through thistle funnel and heated then a mixture of CO and CO2 gas is formed. The mixture of gas is passed through a bottle containing NaOH solution where the CO2 gas is absorbed by NaOH.
2NaOH + CO2 → Na2CO3 + H2O
The pure CO gas is then collected in a gas jar by downward displacement of water.
why is unit of pressure called a derived unit ?? 2) how do you measure the volume of milk?
1. Unit of pressure called a derived unit because it is a combination of base units (kg·m^-1·s^·2).
2. We measure the volume of milk by a instrument called Milk Lactometer.
Describe the principle and process for the manufractured of sulphuric acid witha a well labeled diagram by contact process.
The steps involved in the manufacture of sulphuric acid by contact process:
(1) Sulphur (or iron pyrites) are burnt in air to form sulphur dioxide.
S+O2→SO24FeS2+11O2→2Fe2O3+8SO2
(2) Catalytic oxidation of sulphur dioxide to sulphur trioxide.
2SO2+O2V2O52SO3ΔrHo=−196.6kJ
The reaction is reversible and exothermic.
(3) Sulphur trioxide is dissolved in 98% sulphuric acid to form oleum (fuming sulphuric acid).
SO3+H2SO4→H2S2O7
(4) Oleum is diluted with water to form sulphuric acid of desired concentration.
H2S2O7+H2O→2H2SO4
and
Manufacture of H2SO4 by contact process involves three steps:
1. Burning of sulphur in air to generate SO2.
2. Conversion of SO2 to SO3 by oxidation with air in the presence of
A car of 1200 kg is moving with a speed of 36 Km/hr. It is stopped by applying brakes withion with in 5 seconds. Calculate the amount of force required to stop the car.
Answer:
–2400 N
Explanation:
This is a physics question. However, the answer to the question is given below.
We'll begin by converting 36 Km/hr to m/s. This can be obtained as follow:
3.6 Km/hr = 1 m/s
Therefore,
36 Km/hr = 36 Km/hr × 1 m/s / 3.6 km/hr
36 Km/hr = 10 m/s
Thus, 36 Km/hr is equivalent 10 m/s.
Next, we shall determine the acceleration of the car. This can be obtained as follow:
Initial velocity (u) = 10 m/s
Final velocity (v) = 0 m/s
Time (t) = 5 s
Acceleration (a) =?
a = (v – u) / t
a = (0 – 10) / 5
a = – 10 / 5
a = –2 m/s²
Finally, we shall determine the force required to stop the car. This can be obtained as follow:
Mass (m) = 1200 Kg
Acceleration (a) = –2 m/s²
Force (F) =?
F = ma
F = 1200 × –2
F = –2400 N
NOTE: The negative sign indicate that the force is in opposite direction to the motion of the car.
Identify each of the highlighted materials as an element, a compound, or a mixture, and explain your reasoning.
Answer:
These are compounds.
Explanation:
As it is formed by chemically bonding of two elements C ( carbon) and H (hydrogen) .
Its not a mixture because mixture is Just dispersed of diferrent elements or a compound which are not in fix ratioAnswer:
Butane and benzene are both compounds. They contain multiple elements bonded together in a specific ratio. Kerosene and gasoline are mixtures because they are combinations of several compounds. Oxygen is an element because it is made up of only one type of atom.
Explanation:
differentiate between Physical and chemical changes
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
I HOPE THIS WILL HELP YOU IF NOT THEN SORRY HAVE A GREAT DAY:)7. What measures are applicable in the context of Nepal to push energy crisis further. Describe any three points clearly.
Answer:
which energy?........
Explanation:
..........................
........
....
What is known about a reaction with a positive enthalpy?
Answer:
"Endothermic reaction: In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings of the reaction."
Explanation:
When enthalpy is positive and delta H is greater than zero, this means that a system absorbed heat. This is called an endothermic reaction. When enthalpy is negative and delta H is less than zero, this means that a system released heat. This is called an exothermic reaction.
What does a high positive enthalpy mean?
The sign of q for an endothermic process is positive because the system is gaining heat. A chemical reaction or physical change is exothermic if heat is released by the system into the surroundings. Because the surroundings are gaining heat from the system, the temperature of the surroundings increases.
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Water glass is found in
A. Liquid form at room temperature
B. solid state at room temperature
c. semi liquid form at room temperature
D. None of above
Answer:
liquid form
Explanation:
am i right? if right like
Answer:
semi-liquid at room temperature
distinguish between sugar and non-sugar with examples.
Answer:
Reducing sugars are sugars where the anomeric carbon has an OH group attached that can reduce other compounds. Non-reducing sugars do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds. ... Maltose and lactose are reducing sugars, while sucrose is a non-reducing sugar
What process is used to refine aluminum from its ore bauxite?
A. Electrolysis
B. Electrolytic oxidation
C. Voltaic cell processing
D. Smelting
The correct option for the process used to refine aluminum from its bauxite ore is option D.
D. Smelting
The reason why smelting is the correct choice is as follows;
Bauxite is the aluminum ore from which alumina, also known as aluminum
oxide, Al₂O₃, is produced. Bauxite is extracted from the topsoil regions of
some subtropical and tropical regions, and the Bayer process is primarily
then used to produce alumina from the bauxite.
Aluminum is produced from the alumina by an aluminum smelting process
known as the Hall—Heroult electrolytic process which involves the use of a
carbon anode and direct current to produce aluminum by reducing the
aluminum oxide
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Determine the grams of sodium chloride produced when 10 g of sodium react with 10 grams chlorine gas according to the equation 2Na + Cl2 = 2 NaCl
Answer:
16 g
Explanation:
Step 1: Write the balanced equation
2 Na + Cl₂ ⇒ 2 NaCl
Step 2: Identify the limiting reactant
The theoretical mass ratio (TMR) of Na to Cl₂ is 46:71 = 0.65:1.
The experimental mass ratio (EMR) of Na to Cl₂ is 10:10 = 1:1.
Since EMR > TMR, Cl₂ is the limiting reactant
Step 3: Calculate the mass of NaCl produced
The theoretical mass ratio of Cl₂ to NaCl is 71:117.
10 g Cl₂ × 117 g NaCl/71 g Cl₂ = 16 g NaCl
Calculate the amount of mole(s) of CoF2 required to react with 12.8 moles of HCI.
CoCl2 + 2HF --> CoF2 + 2HCI
Explanation:
here's the answer to your question
At what approximate temperature and pressure can all three phases of water exist simultaneously?
0°C, 760 mmHg
0°C, 5 mmHg
80°C, 380 mmHg
100°C, 760 mmHg
Answer:
0⁰c , 5 mmHg
Explanation:
Because at this temperature we all know water can be in state of both solid and liquid and when pressure is decreased it can be in form of gas too
The atomic mass of calcium is calculated by adding the mass (amount) of
A) Protons and Electrons
B) Protons and Neutons
C) Electrons and Neutons
D) Protons and Protons
Answer:
B. Protons and Neutrons
Answer:
Option"B" is correct.
MARK ME BRAINLISTS
PLZ HELP ME WITH MY WORK
Answer:
Explanation:
pretty sure its mixure.
All three states of matter can be ____________ or a solvent in a solution.
Identify an element as a metal or a non-metal according to its position in the Periodic
Table
Answer:
Metals on the left of the Periodic Table.
Non-Metals on the top-right, plus Hydrogen.
What are isotopes_???
Answer:
Below!
Explanation:
Isotopes are elements with a similar chemical makeup and the same atomic number, but a different atomic mass and number of neutrons . An example of this would be carbon-12, carbon-13, and carbon-14. Three isotopes of the element carbon that have the same 6 protons but have a different neutron count. A simple way to explain isotopes would be to say that they are just different "versions" of an element.
Hope this helps ya! Best of luck <3
what apparatus is used to investigate the conductivity of solutions
what is meant by reaction element
Answer: A reaction element are those elements that can take part in a chemical reaction.
Explanation:
An element is made up of atoms that has the same atomic number. It is the basic material of which all matter is composed of. These elements cannot be broken down further into smaller substances by any chemical reaction. Each element has a unique number of protons in its atom. For example,
--> a hydrogen atom has 1 proton,
--> a Helium atom has 2 protons,
--> a Lithium atom has 3 protons, and
--> a carbon atom has 6 protons.
A chemical reaction on the other hand involves rearrangement of the constituent atoms of reactants to create different substances as products. The bonds between atoms are either broken or created to form new molecules. There are different types of chemical reaction which includes:
--> Decomposition reaction
--> Neutralization reaction
--> single displacement reaction and
--> combustion reaction.
Assertion: Atomic mass of aluminium is 27 Reason: An atom of aluminium is 27 times heavier than 1 / 12th of the mass of the C – 12 atoms.
Answer:
i is the correct answer.
Explanation:
the RAM of aluminum is indeed 27. And since the RAM of substances are measured in terms of the C-12 isotope then R indeed explains why the RAM Al is 27.
2500m into kilometer
1 meter = 1000 km
2500 meter = 2500/1000 km
= 2.5 km
True or false, The four units that must always be used when using the ideal gas are 44.0 liters
Answer:
for volume only liters can be used
Explanation: