What is the percentage of OH- in Ca(OH)2

Answer:

i metal

ii nonmetal

iii metal

iv nonmetal

Explanation:

If you look up what the element of a heater is, you get a picture of some sort of rod. It's the heating element of the heater, and must be some type of metal to conduct electricity and warm up. Fishing rods are made of either fiberglass, graphite, or carbon fibre. These are nonmetals. In order for a lightning rod to conduct electricity and bring the lightning down to the ground, it has to be metal. You wouldn't want a metal oven mitt, as that would burn your hand.

Answer:

Hope this helps you

Answer:

2+

Explanation:

Apex lolz

Answer:

Explanation:

Properties of metals:

1. They have a lustre ( shine )

2. They have a silvery-grey or golden-yellow colour.

3. They conduct heat and electricity.

4. They are ductile ( can be drawn into wires ) .

5.They are malleable ( can be hammered into thin sheets ).

6. They are sonorous ( make a ringing sound when hit ).

Properties of non-metals:

1. They display a variety of colours.

2. They are poor conductors of heat and electricity.

3. They are not lustrous, ductile or malleable.

Hope it helps

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Answer:

c

Explanation:

thw observation of water that is added

Answer:

1.89g of HNO3

Explanation:

Data obtained from the question include:

Mass of water = 31.5 g

Molality of HNO3 = 0.950 m

Mass of HNO3 =.?

Next, we shall determine the number of mole of HNO3 in the solution.

Mass of water = 31.5 g = 31.5/1000 = 0.0315 Kg

Molality of HNO3 = 0.950 m

Number of mole of HNO3 =..?

Molality is simply defined as the mole of solute per unit kilogram of solvent (water) i.e

Molality = mole /kg of water

With the above formula, the mole of HNO3 can be obtained as follow:

Molality = mole /kg of water

0.950 = mole of HNO3 /0.0315

Cross multiply

Mole of HNO3 = 0.950 x 0.0315

Mole of HNO3 = 0.03 mole

Finally, we shall convert 0.03 mole of HNO3 to grams. This is illustrated below:

Molar mass of HNO3 = 1 + 14 + (16x3) = 63g/mol

Mole of HNO3 = 0.03 mole

Mass of HNO3 =..?

Mole = mass /molar mass

0.03 = mass of HNO3 /63

Cross multiply

Mass of HNO3 = 0.03 x 63

Mass of HNO3 = 1.89g

Therefore, 1.89g of HNO3 is needed to prepare the solution.

Answer:

a. 82.68 g b. 9.8 min

Explanation:

a. The amount of gold deposited by 5 A current in 2 hrs 15 mins

Since charge Q = It where I = current = 5 A and time = 2 hrs 15 mins = 2 × 60 min + 15 min = 120 + 15 min = 135 min = 135 × 60 s = 8100 s

Q = 5 A × 8100 s

= 40500 C

Also, Q = nF where n = number of moles of gold deposited and F = Faraday's constant = 96500 C

n = Q/F = 40500 C/96500 C = 0.4195 moles ≅ 0.42 mole

Now n = m/M where m = mass of gold and M = molar mass of gold = 197

m = nM

= 0.42 × 197 g

= 82.68 g

b. The time taken for 6g of gold to be deposited.

We first find the number of moles of gold in 6g of gold

Since n = m/M and m = 6 g

n = 6/197 = 0.0305 mole

Q = It = nF

t = nF/I

= 0.0305 mol × 96500 C/5 A

= 2939.09 mol C

= 587.82 s

Changing t to minutes

587.82/60 s = 9.8 min

Answer:

time for sulphur dioxide to diffuse is 221.05 secs

The time for sulphur dioxide to diffuse is 108 sec.

Sulfur dioxide has a molecular weight of sixty-four and as a result, the square root is 8. since its inversely proportional, on the way to diffuse two times as fast, the rectangular root of the molecular weight should be 4, and subsequently the molecular weight might be 16. So the solution is methane (CH4).

The charge of diffusion for a gas is inversely proportional to the rectangular root of its molecular mass (Graham's law). The gasoline with the lowest molecular weight will effuse the fastest. The lightest, and consequently fastest, fuel is helium.

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Answer:

photosynthesis maybe

Explanation:

bare with me i may be wrong or i may be right it's been a while since i've been in a chem classroom. so basically during photosynthesis a plant is taking the energy from the sun, H2O, and CO2, this ends up being like 6CO2 + 6H20 + (energy), and it converts this energy to glucose (→ C6H12O6 + 6O2 ) so the energy is never used up in this process it is merely changed. i don't really know but i hope it at least helps some

Answer:

Diagram B shows the correct arrangement of electrons in the product.

Magnesium reacts with fluorine to form magnesium fluoride two electrons of magnesium are transferred to the 2 atoms of fluorine and fluorine is the most electronegative element of the periodic table. Option C is correct.

Electronegativity is the tendency or power of an atom to attract the electrons from the metals they are mostly nonmetals and want to complete their octave too.

The most electronegative elements of the periodic table are oxygen, nitrogen, and fluorine, as they are always willing to complete the octave, and fluorine will take electrons from magnesium.

Therefore, Option C is correct if the 2 atoms of fluorine and fluorine are the most electronegative element of the periodic table. Magnesium reacts with fluorine to form magnesium fluoride two electrons of magnesium are transferred.

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Answer:

C. If Assertion is true statement but Reason is false.

Explanation:

The burning of magnesium in air produces magnesium oxide as shown by the equation;

2Mg(s) + O2(g) -----> 2MgO(s)

The magnesium oxide solid is recovered as a white ash. This is a typical example of an oxidation reaction which is also a combustion reaction.

The reason has nothing at all to do with the assertion hence the answer given.

Magnesium oxide is basic just like the oxides of other metals and dissolves in water to yield an alkali.

Answer:

Answer:

C. If Assertion is true statement but Reason is false.

Explanation:

The burning of magnesium in air produces magnesium oxide as shown by the equation;

2Mg(s) + O2(g) -----> 2MgO(s)

The magnesium oxide solid is recovered as a white ash. This is a typical example of an oxidation reaction which is also a combustion reaction.

The reason has nothing at all to do with the assertion hence the answer given.

Magnesium oxide is basic just like the oxides of other metals and dissolves in water to yield an alkali.

Explanation:

Answer:

biomass is renewable

solar is renewable

coal is non-renewable

natural gas is non-renewable

oil is non-renewable

geothermal energy is renewable

Explanation:

The biomass, solar and geothermal are renewable source of energy and coal, natural gas and oil are non renewable source of energy.

Renewable energy is defined as the energy derived from natural source of energy that are replenished at the higher rate then they are consumed.

It can also be defined as the energy that are collected from renewable resources that are replenished on a human time scale.

Solar, wind, tidal, biomass, geothermal etc. are some of the example.

Non renewable energy is defined as the natural resource of energy that cannot be easily replaced by human means at a pace quickly enough to keep up with the consumption.

Coal, petrol, oil, natural gas, fossil fuel etc. are some of the example.

Thus, the  biomass, solar and geothermal are renewable source of energy and coal, natural gas and oil are non renewable source of energy.

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Answer:

True

Explanation:

Phislosophy does not accept something even though it is a khown fact unless it can proves it's true .

Descartes sais that in philosophy we must doubt the facts we khow , we must start from the beginning to reach the truth

answer:

a)1.274 g b) 0.013 mole

Explanation:

a) Mass of 1 mol of CuSo4. 5H20=

[tex]63 + 32 + (16 \times 4) + (7 \times 1) + (16 \times 5)[/tex]

=246g

no. moles of CuSo4. 5H2O=

[tex] \frac{mass}{mass \: of \: 1mole} [/tex]

so moles

=

[tex] \frac{3.14}{246} [/tex]

0.013 mole

in the equation

1 mole of sulphuric acid reacts to form 1 mole of CuSo4.5H2O

in other words

0.013 mole of sulphuric acid reacts to form 0.013 mole of CuSo4.5H2O

so mass of 1 mole (Mr) H2So4=

[tex](2 \times 1) + 32 + (16 \times 4)[/tex]

98g

mass of sulphuric acid= mole × mass of 1 mole

so mass= 0.013 × 98

1.274 g

b) In the equation

1 mole of sulphuric acid reacts to form 1 mole of copper(ll) oxide

in other words

0.013 mole of sulphuric acid reacts to form 0.013 mole of copper (ll) oxide

so 0.013 mole of copper(ll) oxide is reacted

Hope it helped and pls mark brainliest

Answer:

What are the periodic trends of ionic radii? Check all that apply.

*Ionic radii tend to increase down a group.

Ionic radii tend to decrease across a period.

Anionic radii tend to increase across a period.

*Cationic radii tend to decrease across a period.

*Ionic radii increase when switching from cations to anions in a period.

Answer:

- Ionic Radii Tend To Increase Down A Group.

- Cationic Radii Tend To Decrease Across A Period.

- Ionic Radii Increase When Switching From Cations To Anions In A Period.

Explanation:

i got it correct on edge

Answer:

transports solid materials

Explanation:

Erosion is a process where solid materials are transported by natural forces such as wind or water.

Answer: c

Explanation:

Answer:

1:1

Explanation:

There is one mole of zinc (Zn) and one mole of zinc sulfate (ZnSO₄).

The mole ratio is 1:1.

Hope this helps.

Answer:

1:1

Explanation:

Answer:

Answers are in the explanation

Explanation:

Precision and accuracy are both statistical concepts. Precision is about how close are the measured values to each other. Accuracy is closeness of the measured values to a specific value or reference value.

There are many ways to calculate precision and accuracy, one is stimating precision as Relative Uncertainty and accuracy as Relative Error.

Formulas are:

Relative Uncertainty: Standard desviation /  Measured value.

Relative Error: Measured Value - Expected Value / Expected value

Measured value is the aveage of the values.

For student 1:

Mean = 25

Standard desviation = 1.5275

Relative Uncertainty: 1.5275 /  25

Relative Uncertainty: 0.061

Relative Error: 25 - 20 / 20

Relative Error: 0.25

For student 2:

Mean = 24.5

Standard desviation = 0.5477

Relative Uncertainty: 0.5477 / 24.5

Relative Uncertainty: 0.02

Relative Error: 24.5 - 20 / 20

Relative Error: 0.225

As the student 2 has a low Relative error and uncertainty, you can say student 2 is more accurate and precise

Answer:

You should get the catalyst back already.

Explanation:

A catalyst shouldn't be used up during a chemical reaction. It is used to speed up a reaction, but it shouldn't disappear/be used up by a chemical reaction.

Answer:OD. Producing light

Explanation:

Answer: ammonium chloride

Explanation: The reaction equation among ammonia (NH3) and hydrochloric acid (HCl) is written as follows: NH3+HCl=NH4Cl. Ammonia is a susceptible base that reacts with hydrochloric acid, forming a compound referred to as ammonium chloride.

Answer:

A.

Explanation:

The amount of mass always stays the same, matter cannot be created nor destroyed, it can only change forms. Thus, the answer is A.  

In a chemical reaction the total mass of all the substances taking part in the reaction remains the same. Also, the number of atoms in a reaction remains the same. Mass cannot be created or destroyed in a chemical reaction.

I hope this helps..

Answer:

A. It is exothermic

Explanation:

Combustion is a chemical reaction in which a substance combines with oxygen present in air to produce carbon (iv) oxide and water as well release  heat and light energy.Combustion is an exothermic process.

An exothermic reaction releases energy in the form of heat to the surroundings. The energy required to break bonds in the reactants is less than the energy required to form new bonds in the products in an exothermic reaction.

From the given options;

A. It is exothermic is determinable since the reaction is a combustion reaction

B. The bond making energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather it is composed of various substances.

C. It is endothermic. is wrong because combustion of wood is exothermic.

D. The bond breaking energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather is composed of many substances.

Answer:

c. Chemical bonds are broken, and new ones are formed.

Explanation:

Hope this helps. :)

In a chemical reaction, chemical  bonds are broken, and new ones are formed.

Chemical reactions are defined as reactions which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical reaction.

There are several characteristics of chemical reactions like change in color, change in state , change in odor and change in composition . During chemical reaction there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical reactions:

1) inorganic reactions

2)organic reactions

3) biochemical reactions

During chemical reactions atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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Answer:

D). The rate increases because a higher temperature means that particles move at higher speeds and there are more collisions in the system.

Explanation:

The rate of the given chemical reaction would rapidly increase with an increase in temperature as the higher temperature will increase the kinetic energy possessed by the reactant molecules. This will lead to the movement of particles at a higher speed and more effective collisions will take place(as the greater proportion of molecules will have the energy required for collision). Thus, the last statement correctly justifies this description and hence, option D is the correct answer.

Answer:

An exothermic reaction is a chemical reaction in which energy is given out to the surroundings in the form of heat or light or even sound.

Other explanations are given below.

Explanation:

An exothermic reaction is a chemical reaction in which energy is given out to the surroundings in the form of heat or light or even sound. In exothermic reactions, the energy content of the products are lower than that of the reactants and this excess energy is therefore released as the reaction proceeds towards formation of products.

Combustion of fuel is an exothermic reaction because the process involves the  release of energy in the form of heat and light to the surroundings as the reactants (usually a fuel and oxygen) which are at a higher energy state combine to give the products which are at a lower energy state (usually CO₂ and water).

An example of a fuel is the gas propane found in cooking gas. It combines with oxygen found in air to produce the heat that is used to cook our foods.

Other examples of exothermic reactions include

1.Lighting firewood: In this process, wood which is a mixture of gaseous fuels like methane and solid fuel like charcoal combine with oxygen found in air to produce carbon (iv) oxide and water vapor while releasing heating the process.

2. Lighting a match: The head of safety matches are made of potassium chlorate, mixed with sulfur, fillers and glass powder.  The side of the box contains red phosphorus, binder and powdered glass. When the match is struck, the friction generates heat which causes a small amount of red phosphorus to be converted to white phosphorus, which then ignites spontaneously in air.  The heat produced initiates the decomposition of potassium chlorate to give oxygen and potassium chloride.  The sulfur catches fire and ignites the wood which also burns in the air to release carbon (iv) oxide an water.

3. Burning of coal: Coal is solid carbon which combines with oxygen in air when ignited to produce carbon (iv) oxide and water vapor while also releasing heat and light energy.

Answer:

Hope this helps you

Answer:

The gas cloud must be very dense.Temperatures must exceed 14 million Kelvin

Nuclear fusion is the process in which atomic nuclei come together to form heavier nuclei, releasing large amounts of energy in the process. The correct statements are The gas cloud must be very dense, Atoms must be stripped of their electrons, and Temperatures must exceed 14 million Kelvin.

For fusion to occur, certain conditions must be met. The gas cloud or plasma must be dense enough to allow for a sufficient number of collisions between atomic nuclei. Gravitational attraction, on the other hand, is necessary to bring the atomic nuclei close enough together for the strong nuclear force to overcome the electrostatic repulsion between positively charged nuclei.

Atoms must be stripped of their electrons because, in a plasma state, the atoms are ionized, meaning they have lost or gained electrons and exist as charged particles.

Hence, the correct statements are The gas cloud must be very dense, Atoms must be stripped of their electrons, and Temperatures must exceed 14 million Kelvin.

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