Help answer these chemistry questions

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.

Answer:

option C 11

is the correct answer

Answer:

1. Fr

2. cl

3.H20

4.2 mole

5. 3

6. c

Answer: Aqua fortis is also known as Nitric Acid  

Explanation: and the process in making aqua fortis is THE OSTWALDS PROCESS

detailed explanation by me

ammonia is also used in this process, which is reacted with oxygen and water and a catalyst platinum.

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The answer is C.

The vast difference in electronegativity of the oxygen and hydrogen in water, the O-H bond is polar.

The characteristic of water that makes it cohesive in nature is that It has a vast electronegativity difference between its atoms. So, option C is correct one.

The water molecule contains two hydrogen atoms and oxygen atom.

The electronegativity of hydrogen atoms and oxyegen atom is 2.1 and 3.44

Due to high electronegativity of oxygen ,it can attract the bonded pair of electron of hydrogen and form a strong bond and make it cohesive in nature.

The water molecule have unique characteristics among all some are given below.

Water is polar, with partial positive charge on two hydrogen and partial negative charge on one oxygen.

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Answer:

Option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).

Explanation:

To know if a solution is acidic we need to calculate the pH and it must be lower than 7. A value of pH equal to 7 is a neutral solution and a solution with a pH value higher than 7 is a basic solution.

a. For the [OH⁻] = 7.0x10⁻⁹ M we have:

[tex] pOH = -log[OH^{-}] = -log(7.0 \cdot 10^{-9}) = 8.15 [/tex]

Now, the pH is:

[tex] pH + pOH = 14 [/tex]

[tex] pH = 14 - pOH = 14 - 8.15 = 5.85 [/tex]

This solution is acidic (pH < 7)

b. [H₃O⁺] = 8.5x10⁻⁸ M

[tex] pH = -log(8.5 \cdot 10^{-8}) = 7.07 [/tex]

This is not an acidic solution. Is a neutral one (pH around to 7).

c. [OH⁻] = 2.5x10⁻⁶ M

[tex] pOH = -log[OH^{-}] = -log(2.5 \cdot 10^{-6}) = 5.60 [/tex]

Then, the pH is:

[tex]pH = 14 - pOH = 14 - 5.60 = 8.40[/tex]

Hence, this is not an acidic solution. It is basic (pH > 7).    

Therefore, option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).

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Answer:

the reactants are carbon dioxide ,iron, oxygen

Answer:

CuO + H2SO4 = CuSO4 + H2O  

Reaction type: double replacement

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.

D. Water is used up, Oxygen is produced and Chlorophyll is necessary, but remains unchanged.

The number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.

The mass of a substance can be calculated by multiplying the number of moles by its molar mass.

However, the number of moles of helium must be calculated as follows:

PV = nRT

Where;

0.985 × 0.785 = n × 0.0821 × 301

0.773 = 24.7n

n = 0.773 ÷ 24.7 = 0.031moles

mass of He = 0.031 × 4 = 0.125g

Therefore, the number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.

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Answer:

The given statement is False.

The organisms adapt as a result of competition for resources. Different places have different organisms suited for that particular places.

The animals living at a particular place compete for the resources available and the nature selects the organism that has won the competition for resources.

The organisms are evolved as a result of competition for resources

Answer:

I just wanted to say the other person is totally right.

this statement is false.

Answer:

Any individual offspring produced through asexual reproduction is always: genetically identical to its parent. made up of cells with a cell wall. different from all of its siblings

Answer:

to collect pure hydrogen and avoid mixing with air

Answer:

B

Explanation:

the digestive system

Answer: The average percent yield of MgO is 98.59 %.

Explanation:

The chemical equation follows:

[tex]2Mg(s)+O_2(g)\rightarrow 2MgO(s)[/tex]

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of Mg = 0.411 g

Molar mass of Mg = 24.3 g/mol

Plugging values in equation 1:

[tex]\text{Moles of Mg}=\frac{0.411g}{24.3g/mol}=0.0170 mol[/tex]

By the stoichiometry of the reaction:

If 2 moles of Mg produces 2 moles of MgO

So, 0.0170 moles of Mg will produce = [tex]\frac{2}{2}\times 0.0170=0.0170mol[/tex] of MgO

We know, molar mass of [tex]MgO[/tex] = 40.3 g/mol

Putting values in equation 1, we get:

[tex]\text{Mass of }MgO=(0.0170mol\times 40.3g/mol)=0.685g[/tex]

The percent yield of a reaction is calculated by using an equation:

[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)

Given values:

Actual value of the product = 0.675 g

Theoretical value of the product = 0.685 g

Plugging values in equation 1:

[tex]\% \text{yield}=\frac{0.675g}{0.685g}\times 100\\\\\% \text{yield}=98.54\%[/tex]

Hence, the % yield of the product is 98.54 %

Given mass of Mg = 0.266 g

Molar mass of Mg = 24.3 g/mol

Plugging values in equation 1:

[tex]\text{Moles of Mg}=\frac{0.266g}{24.3g/mol}=0.011 mol[/tex]

By the stoichiometry of the reaction:

If 2 moles of Mg produces 2 moles of MgO

So, 0.011 moles of Mg will produce = [tex]\frac{2}{2}\times 0.011=0.011mol[/tex] of MgO

We know, molar mass of  = 40.3 g/mol

Putting values in equation 1, we get:

[tex]\text{Mass of }MgO=(0.011mol\times 40.3g/mol)=0.443g[/tex]

The percent yield of a reaction is calculated by using an equation:

[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)

Given values:

Actual value of the product = 0.437 g

Theoretical value of the product = 0.443 g

Plugging values in equation 1:

[tex]\% \text{yield}=\frac{0.437g}{0.443g}\times 100\\\\\% \text{yield}=98.64\%[/tex]

Hence, the % yield of the product is 98.64 %

Average of a measurement is calculated by given formula:

[tex]Average=\frac{M_1+M_2}{2}[/tex]

where,

[tex]M_1[/tex] = percentage yield for Trial 1 = 98.54 %

[tex]M_2[/tex] = percentage yield for Trial 2 = 98.64 %

Putting values in above equation, we get:

[tex]Average=\frac{98.54+98.64}{2}=98.59\%[/tex]

Hence, the average percent yield of MgO is 98.59 %.

Answer:

Mechanism

explanation:

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D is the answer .. I have send u pic also

hydrated cucl2 have blue-green colour

Answer:

e.

6.7

hope it help

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Answer:

5

Explanation:

The atomic number is the number of protons in an atom. Protons are the positively charged particles in the nucleus. The number of protons define the identity of an element. An element with 5 protons is Boron, no matter how many neutrons may be present.

The atomic number of the atom shown in the diagram is 5.

The atomic number of an element refers to the number of protons in the nucleus of its atoms. It uniquely identifies an element and determines its chemical properties.

In the diagram, there are 5 proton numbers in the nucleus of the atom. In other words, this means that the atomic number of the atom is 5.

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Answer:

A. There is a temperature difference

Explation:

Whenever there is a temperature difference, heat transfer occurs. Heat transfer may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice chest.

Answer:

A.) there is a temperature difference

Explanation:

I got it correct on founders edtell

Answer: Water is SUPER soluble and regarded as an universal solvent because it is polar in nature and dissolves most inorganic solutes and some polar organic solutes to form aqueous solutions.

Explanation:

WATER is a substance which is composed of the elements such as hydrogen and oxygen that are combined in the ratio of 2:1. The physical properties of water include:

--> it is a colourless, odourless and tasteless liquid and

--> the boiling point of water is 100°C(this is due to the presence of hydrogen bonding).

The solubility of a solute in a solvent at a particular temperature is the maximum amount of solute in moles or grams that will saturate 1000 dm³ or grams of the solvent.

Water is regarded as a universal solvent BECAUSE it is capable of dissolving many substances. This solubility helps maintain different processes in life such as acting as the solvent which helps cells transport and use substances like oxygen or nutrients.

Answer:

C) the study of the composition of the atom.

Explanation:

A research can be defined as a systematic investigation or careful consideration of study with respect to a particular problem using scientific methods such as collection of data, documenting critical information, analysis of data, and the establishment of facts in order to reach new conclusions.

Similarly, a basic research is an approach to research that's typically theoritical and it's aimed at developing a theory, searching for the truth or gain a better understanding about a phenomenon, subject, or basic laws on nature.

In this context, an example of basic research is the study of the composition of the atom.

An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.

Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.

Answer:

1.76 g

Explanation:

2HgO(s) ==> 2Hg(l) + O2(g)

Number of moles of Hg = 22.3 g/ 201g/mol

= 0.11 moles

From the reaction equation;

2 moles of Hg is formed alongside 1 mole of oxygen

Hence;

0.11 moles of Hg forms 0.11 moles × 1/2

= 0.055 moles of oxygen

Mass of oxygen formed = 0.055 moles of oxygen × 32g/mol = 1.76 g

Answer:

1.48 moles of SeCl6 are needed

Explanation:

Based on the reaction:

SeCl6 + O2 → SeO2 + 3Cl2

1 mole of SeCl6 reacts producing 3 moles of Cl2.

To solve this question we need to use the conversion factor:

1mol SeCl6 = 3mol Cl2

As we want to produce 4.45 moles of Cl2, we need:

4.45 mol Cl2 * (1mol SeCl6 / 3mol Cl2) =