Answer:
homogeneous mixture must be the answer
I need help with question 5
Answer:
B a spring being stretched
write an importance of endothermic reactions
Answer:
the uses of exothermic reactions are:
1) lighting of stove
2) self heating cans
3) hand warmers
4) in some case exothermic process can be used to cook food such as rice (by adding calcium oxide to water heat is evolved and it helps to cook food )
Explanation:
hope this helps you pls mark me as brainilst
Which element has 2 valence electrons in the 2s sublevel?
Answer:
beryllium is the answer.
I hope this will help you
A sample of gas has a volume of 20 cm³.The pressure is changed to 90 kPa at constant temperature,while the volume increases to 75 cm³.What was the original pressure of the gas?
Answer:
337.5kPa ~ 338kPa
Explanation:
Using the ideal gas law PV=nRT we have the following definitions from the problem:
V(initial) = 20cm³
P(initial) = ?kPa
V(final) = 75cm³
P(final) = 90kPa
Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:
P(initial)V(initial) = nRT =P(final)V(final) ~ P(initial)V(initial) = P(final)V(final)
Rearranging this equation as we are solving for the initial pressure we find that:
P(initial) = (P(final)V(final))/V(initial)
P(initial) = ((90kPa)(75cm³))/20cm³
P(initial) = 337.5kPa ~ 338kPA
the text of oxygen gas in the laboratory
Explanation:in testing for oxygen a glowing splint is used.
the glowing splint is brought in the presence of the test tube containing the gas
the glowing splint rekindles or lights up showing that oxygen is present.
this is a positive test because oxygen supports burning or combustion
Which among the following mixtures will show tyndal effect?
i) copper sulphate solution
ii) sand in water.
iii) milk.
iv) starch solution
Answer:
milk and starch solution are the colloids, hence these will show the tyndall effect
Answer:
milk and starch solution
Explanation:
Tyndall effect is shown by colloidal solutions. It is not shown by true solutions or suspensions.
Milk and starch solution are colloidal solutions. They show tyndall effect. On the other hand, common salt and copper sulphate solution are true solutions. They do not show tyndall effect.
True or false, The universal gas constant, R, is . 0821 when we use mm Hg as our unit for pressure
Answer:
False
Explanation:
R = gas constant = 0.0821 atm•L/mol•K
Which equation describes a physical change? i. H2O(s) ⟶ H2O(l) ii. Na+(aq)+Cl−(aq) +Ag+(aq)+NO3−(aq) ⟶ AgCl(s)+Na+(aq)+NO3−(aq) iii. CH3OH(g)+O2(g) ⟶ CO2(g)+H2O(g) iv. 2H2O(l) ⟶ 2H2(g)+O2(g) v. H+(aq)+OH−(aq)⟶ H2O(l)
Answer:
The answer is "Option i"
Explanation:
In this question, only option (i) is correct, and others were wrong which can be defined as follows:
In option (ii):
[tex]Na^+\ (aq)+Cl^- \ (aq) +Ag^+ \ (aq)+NO_3^- \ (aq) \to AgCl\ (s)+Na^+ \ (aq)+NO_3^-\ (aq) \\\\[/tex]
It is the complete ionic equation.
In option (iii):
[tex]CH_3OH\ (g)+O_2\ (g) \to CO_2\ (g)+H_2O\ (g)[/tex]
It is the combustion reaction but a not balanced equation.
In option (iv):
[tex]2H_2O\ (l) \to 2H_2\ (g)+O_2\ (g)[/tex]
It is the decomposition equation.
In option (v):
[tex]H^+\ (aq) +OH^-\ (aq)\to H_2O\ (l)[/tex]
It is the complete ionic equation.
Plants in forests take up carbon dioxide from the atmosphere during photosynthesis. They transform the carbon dioxide into plant material. When plants die, their organic matter is often worked into the soil by decomposers. Some of this organic matter remains within the soil and forest floor, and some of it is taken up by other living things.
Based on this information, what role do forests play in the carbon cycle?
A.
Forests are carbon sinks because they store carbon.
B.
Forests are carbon sinks because they do not absorb carbon dioxide when plants die.
C.
Forests are carbon sources because they emit carbon.
D.
Forests are carbon sources because they can be burned to emit carbon dioxide.
Answer: B. forests are carbon sinks because they store carbon
Explanation:forests take up carbon from the atmosphere through photosynthesis and from organic matter through decomposition. so, forests are carbon sinks because they store carbon
difference between Nitrogen 1 oxide and Oxygen
Answer:
one atom of oxygen is not equal to oxygen
What is the pressure in atm exerted by 1.8 g of H2 gas exert in a 4.3 L balloon at 27ºC? R = 0.821(L*atm) / (mol*K)
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The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
What is Ideal gas law ?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
Let's convert grams to moles (via molar mass).
Molar Mass (H₂) : 2 (1.008 g/mol)
Molar Mass (H₂) : 2.016 g/mol
1.8 grams H₂ 1 mole
---------------------- x ---------------------- = 0.893 moles H₂
2.016 grams
The Ideal Gas Law equation looks like this:
PV = nRT
In this equation,
P = pressure (atm) V = volume (L) n = moles R = Ideal Gas Constant (0.0821 L*atm/mol*K)T = temperature (K)After converting Celsius to Kelvin, you can put the given values into the equation and simplify to find the pressure.
P = ? atm R = 0.0821 L*atm/mol*K
V = 4.3 L T = 27 °C + 273.15 = 300.15 K
n = 0.893 moles
PV = nRT
P (4.3 L) = (0.893 moles) (0.0821 L*atm/mol*K)( 300.15 K)
P (4.3 L) = 22.0021
P = 5.12 atm
Therefore, The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
Learn more about Ideal gas here ;
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A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.
Fl atomic number: 9
Fl atomic mass: 10
(ps i have two of these but can’t figure out the last)
Answer:
The number of electrons in the orbit is wrong they have to be 9 and not 10since flourine is in group 7 the number of electrons in the outer most shell has to be 7 and not 2the first shell has 8 instead of 2 electronsI hope this helps
Please help with the Volume one
Answer:
im a just achild
Explanation:
Answer:
c
Explanation:
0.5dm³
follow me if you want
write any two conditions at which a body of certain mass weightless
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity. If the body is falling only under the influence of gravity.
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity.If the body is falling only under the influence of gravity.
Is this population more likely to grows slowly or quickly in the next 10 years
nobody can say it is uncertain but in my opinion it will grow quickly in the next 10 years
Which of the following molecules contains six bonding electrons?
A C2H4
B CO2
C H2S
D NCl3
Answer:
c2h4 (etthane........
bexcuse it has 6 bond of hydrogen
C₂H₄ molecules contains six bonding electrons. Therefore, option A is correct.
What do you mean by the term bonding ?Chemical bonding is the process through which two or more atoms, molecules, or ions establish a chemical link to create a chemical compound. The atoms in the resultant molecule are held together by these chemical bonds.
Chemical bonds have three basic characteristics that must be taken into account: their strength, length, and polarity. The distribution of electrical charge among the atoms connected by a bond determines its polarity.
C₂H₄ molecules has six bonding electrons. This molecule is called as Ethylene. When bonding is done between two atoms, each atom shares a pair of electrons with each other.
Hence, for every one bond, two electrons are shared between two atoms
Thus, option A is correct.
To learn more about the bonding, follow the link;
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How many atoms of hydrogen are there in 36 g of NH4?
Answer:
hope it helps you
Explanation:
please like and mark me brainlist
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.
what is a cubic unit cell ?
cubic unit cell is the smallest repeated unit which have all angles equal to 90 and all have edge lengths equal
It is the type of the Unit cell which is having all angles equal to 90 and all sides equal to each other
it's is a unit cell with cubic structure
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
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:
Cho các dung dịch: Glucozơ, glixerol, fomanđehit, etanol. Có thể dùng thuốc thử nào sau đây để phân biệt được cả 4 dung dịch trên?
A. Cu(OH)2; B. Dung dịch AgNO3 trong NH3;
C. Na kim loại; D. Nước brom.
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Answer:
chắc là câu B í
Explanation:
Can you help me on this. I will support your correct answer
Please help I have been stuck on this problem for a couple hours and can't figure it out
Answer:
11.92 Liters O₂(g) at STP
Explanation:
For most stoichiometry problems, if one will convert all given data into moles, solve by rxn ratios, then finish by converting to needed dimensions to complete problem.
2Pb(NO₃)₂ => 2PbO + 4NO₂ + O₂
Given 237.5 grams PbO formed in reaction = 237.5 g/223.2 g/mole = 1.064 mole PbO
From equation ratios, moles O₂ formed = 1/2(moles PbO) = 1/2(1.064 moles O₂) = 0.532 mole O₂
0.532 mole O₂ = 0.532 mole x 22.4 liters/mole at STP = 11.91756272 liters (calculator answer) ≅ 11.92 liters O₂ at STP (4 sig.figs. based on given 237.5g PbO)
Is FeS iron (ll) sulfide or iron (lll) sulfide?
Answer:
the valence of S is -2. For FeS to be neutral the valence of Fe used must be +2
and since Iron (II) has its valency 2, FeS will be Iron (II) Sulfide.
Describe weighted average
Answer:
Explained below
Explanation:
In simple average, we just add all the given data variables and divide it by the number of data given.
However, when it comes to weighted average, what we do is that we multiply each given variable by their weights and then divide the sum of that by the sum of the weights.
Thus, if the variables are denoted by x and their weights are denoted by y, then we have;
Weighted average = Σ(xy)/Σy
How are the vapor pressure and boiling point of alkynes affected as the chain length increases?
Answer:
Answer to the following question is as follows;
Explanation:
Alkynes' vapour pressure and normal boiling points are altered when chain length grows, since vapour pressure rises while boiling point falls.
Vapour pressure always include pressure entered by vapour with its condensed phase, pressure include molecules force of attraction include vapour
what apparatus is used to investigate the conductivity of solutions
When it’s summer in the northern hemisphere what Season is it in the Southern Hemisphere
Answer:
Winter
Explanation:
I dont know but whatev
Answer:
Winter
Explanation:
The seasonal cycle in the polar and temperate zones of one hemisphere is opposite to that of the other. Therefore, When it is summer in the Northern Hemisphere, it is winter in the Southern, and vice versa.
hope it helps :)
mention two factors which affect pressure due to liquid contained in a vessel
Answer:
depth of the liquid and nature of liquid affects the pressure due to liquid contained in a vessel
Answer:
Two factors influence the pressure of fluids. They are the depth of the fluid and its density. A fluid exerts more pressure at greater depths
