Please help with the Volume one

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

Answer:

False

Explanation:

R = gas constant = 0.0821 atm•L/mol•K

Answer:

C.[tex]3.8\times 10^{-2}[/tex]

Explanation:

We are given that

Initial concentration, [tex][A]_o=4.3 M[/tex]

First half life, [tex]t_{\frac{1}{2}}=56[/tex]minutes

Second half life, [tex]t'_{\frac{1}{2}}=28[/tex]minutes

We have to find K.

The given reaction is zero order reaction.

We know that for zero order reaction

[tex]t_{\frac{1}{2}}=\frac{[A]_o}{2k}[/tex]

Using the formula

[tex]56=\frac{4.3}{2k}[/tex]

[tex]k=\frac{4.3}{2\times 56}[/tex]

[tex]k=3.8\times 10^{-2}[/tex]

Hence, option C is correct.

Zero-order reactions are the reactions when a surface or a catalyst is required for the reaction to proceed and is saturated by the reactant chemicals. The result of the concentration versus the time plot will be a straight line in a zero-order reaction.

[tex]3.8 \times 10 ^{-2}[/tex] is the value of k.

Given,

The given reaction in the question is of zero-order and for that, we know that,

[tex]t \dfrac{1}{2} = \dfrac{[A_{0}] }{2\;\rm k}[/tex]

Substituting the values in the equation we get:

[tex]\begin{aligned}56 &= \dfrac{4.3 }{2\; \rm k}\\\\\rm k &= {4.3 }{2 \times 56}\\\\\rm k &= 3.8 \times 10^{ -2}\end{aligned}[/tex]

Therefore, option C is correct.

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Answer:

The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other

The compounds formed includes;

1) Nitric oxide, NO

Nitrogen = 46.66% × 30.01 = 14

Oxygen = 53.34% × 30.01 = 16

2) Water, H₂O

Hydrogen = 11.21% × 18.01528 = 2

Oxygen = 88.79% × 18.01528 ≈ 16

3) Ammonia, NH₃

Hydrogen = 17.78% × 17.031 ≈ 3

Nitrogen = 82.22% × 17.031 ≈ 14

The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8

The ratio of nitrogen to hydrogen in ammonia = 14:3

The ratio in which hydrogen and oxygen combine with nitrogen = 3/16

The ratio of hydrogen and oxygen combine with each other in water = 2/16

Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions

Explanation:

Answer:

hope it helps you

Explanation:

please like and mark me brainlist

Answer:

29.41% of Calcium and 47.04% of Oxygen

Explanation:

The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.

The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:

13.61g / 46.28g * 100 = 29.41% of Calcium

And percent composition of Oxygen is:

21.77g / 46.28g * 100 = 47.04% of Oxygen

Answer:

1.Physical change

2. Chemical change

3. Heat

4.photosynthesis

5. composition

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.

Answer:

B. The amount of produd obtained/amount possible * 100

Explanation:

In chemistry, the yield of a chemical reaction is the quantity or amount of products obtained in that chemical reaction. It is calculated by using the following formula:

Percentage yield = Actual yield/theoretical yield × 100

- The actual yield is the amount of products got from a chemical reaction

- The theoretical yield is the amount of product got from using the balanced equation (stoichiometry).

Answer:

I hope this helps

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

Answer:

This is because Mendeleev arranged the elements in order of increasing relative atomic mass.

Explanation:

Dmitri Mendeleev is one of the scientists that contributed to the development of periodic table in chemistry. He was able to organise elements into rows according to their atomic mass and into columns based on chemical and physical properties. This is the main reason why his periodic table is still studied even though it has some defects which include:

--> Grouping of elements that are not similar chemically: For example Copper and Silver bear no resemblance with the alkali metals, but they have been placed together in the first group.

--> Position of isotopes: According to his periodic table: Isotopes of an element must be given separate places in the periodic table because they have different atomic masses.

--> Electronic arrangement of elements: It failed to explain the electronic arrangement of elements.

--> Separation of chemically similar elements:

Elements that are chemically similar such as Gold and Platinum have been placed in separate groups.

Answer:

chắc là câu B í

Explanation:

Answer:

C. Enlargement

Explanation:

Answer:

I believe it's salt and water

Explanation:

not sure

Answer:

Mixture is a electronic device used to peel the things such as onion ,tomato,ginger, garlic etc.

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

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 :)

Answer:

Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.

Here, we have been given that;

Hence, we can note that,

(n) = 32.05

[tex] \\ [/tex]

Thus,

Hence, molarity of the given solution will be 32.05 mg/L.

Answer:

c2h4 (etthane........

bexcuse it has 6 bond of hydrogen

C₂H₄ molecules contains six bonding electrons. Therefore, option A is correct.

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.

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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

The name of the molecule shown is Ethanol.

Ethanol is a alcoholic substance that is formed from fermentation of glucose in the presence of yeast or microorganisms.

It has a chemical group that have methyl group, hydroxyl group OH which is bonded to carbon atom.

Therefore, The name of the molecule shown is Ethanol.

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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.

Answer:

yes it does

Explanation:

because the ratios on the reactants and products are equal

The reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

Yes, this reaction obeys the law of conservation of mass. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is only rearranged.

In the given reaction, we have 2 sodium atoms (Na) on the left side and 2 sodium atoms (Na) on the right side. Similarly, we have 2 chlorine molecules (Cl₂) on the left side and 2 chlorine atoms (Cl) on the right side. Therefore, the number of atoms of each element is balanced on both sides of the reaction.

Additionally, the total mass of the reactants (2Na + Cl₂) is equal to the total mass of the product (2NaCl). The coefficients in the balanced equation represent the stoichiometric ratios, ensuring that the mass is conserved.

Hence, the reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

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Answer:

Explanation:

Formula

The current = charge / time

The charge is in coulombs

The time has to be in seconds.

1 minute = 60 seconds

2 minutes = 120 seconds.

charge = 180 coulombs

current = 180 / 120

current = 1.5 amperes.

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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

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,

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

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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