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Elements are commonly indicated by a chemical symbol, the atomic number and the mass number.

The nucleon number or mass number is written in the left superscript.

The atomic number or proton number or electronic number is written in the left subscript.

0.025 g of starch needed to prevent coagulation of 1 ml of 10 % NaClto 10 ml gold sol.Amount of starch = 0.025 g = 25 mgSo, gold number of starch = 25

The ice is less dense than water. It means the density of water is more than ice. So, ice floats on the water surface.

When water freezes and forms ice, the particles arrange themselves in a hexagonal structure which increases the surface area....thus the density decreases and ice floats on water.👍👍

ice has less density than water

Yeah

because Ice had less density than water

the density of water is 1g/ml and ice is 0.917g/ml which is less than water therefore ice floats on water

ice floats on water because it has low density (0.92g/cubiccm) than water(1g/cubiccm).

because ice has less density than water

wen can make iron float on water by making it into a thin metal sheet..... which increases the surfacearea.. and thereby increasing the upthrust that is buoyant force.... which makes iron floats on water

Plants create the majority of the oxygen we breathe through a process called photosynthesis. In this process plants use carbon dioxide, sunlight, and water to create energy. In the process they also create oxygen which they release into the air.

thanks

1)BCG, orbacille Calmette-Guerin, is a vaccine for tuberculosis (TB) disease. Many foreign-born persons have beenBCG-vaccinated.BCGis used in many countries with a high prevalence of TB to prevent childhoodtuberculousmeningitis andmiliarydisease.

2) microbes

3) female anopheles mosquito

4)Grapeblack rot is afungal disease causedby an ascomycetousfungus, Guignardia bidwellii, that attacksgrape vines during hot and humid weather.

5)Transmission. The hepatitis A virus istransmittedprimarily by the faecal-oral route; that is when an uninfected person ingests food or water that has been contaminated with the faeces of an infected person.

An isomer of a molecule has the same number of atoms of each element, but has a different arrangement of the atoms. It has the same molecular formula as the other molecule, but with a different chemical structure. Isomers do not necessarily share similar properties, unless they also have the same functional groups.

If there would be no or less rainfall then the water water will not seep down the soil.hence,percolation will not take place and water would no be added to the water table and it lowers down

thanks bro

Fires need oxygen, fuel, and heat to ignite, and removing any one of those three components can put out a fire.

Carbon dioxide extinguishers work because carbon dioxide molecules are heavier than oxygen molecules. When the liquid carbon dioxide inside the extinguisher expands into a gas, the carbon dioxide pushes out any oxygen surrounding the fire. Without oxygen available to fuel the chemical reaction, the fire goes out quickly.

1. False (India is democratic but USA has federal government)2. True3. True4. False5. True6. False (Dictatorship is based on force)

1. False (India is democratic but USA has federal government)2. True3. True4. False5. True6. False (Dictatorship is based on force)

In froth floatation process, advantage is taken of prefferential wetting of ore particles by oil and gangue particles by water.

Pine oil or eucalyptus oil has tendency to wet metal sulphides. Thus sulphide ore is present in oily froth whereas gangue particles settle at the bottom,and hence fuller concentration is achieved.

The goal is simple. Carbon dioxide is the climate’s worst enemy. It’s released when oil, coal, and other fossil fuels are burned for energy—the energy we use to power our homes, cars, and smartphones. By using less of it, we can curb our own contribution to climate change while also saving money. Here are a dozen easy, effective ways each one of us can make a difference:

1. Speak up!What’s the single biggest way you can make an impact on global climate change? “Talk to your friends and family, and make sure your representatives are making good decisions,” Haq says. By voicing your concerns—via social media or, better yet, directly to your elected officials—you send a message that you care about the warming world. Encourage Congress to enact new laws that limit carbon emissions and require polluters to pay for the emissions they produce. “The main reason elected officials do anything difficult is because their constituents make them,” Haq says. You can help protect public lands, stop offshore drilling, and more here.

2. Power your home with renewable energy.Choose a utility company that generates at least half its power from wind or solar and has been certified by Green-e Energy, an organization that vets renewable energy options. If that isn’t possible for you, take a look at your electric bill; many utilities now list other ways to support renewable sources on their monthly statements and websites.

3. Weatherize, weatherize, weatherize.“Building heating and cooling are among the biggest uses of energy,” Haq says. Indeed, heating and air-conditioning account for almost half of home energy use. You can make your space more energy efficient by sealing drafts and ensuring it’s adequately insulated. You can also claim federal tax credits for many energy-efficiency home improvements.

4. Invest in energy-efficient appliances.Since they were first implemented nationally in 1987, efficiency standards for dozens of appliances and products have kept 2.3 billion tons of carbon dioxide out of the air. That’s about the same amount as the annual carbon pollution coughed up by nearly 440 million cars. “Energy efficiency is the lowest-cost way to reduce emissions,” Haq says. When shopping for refrigerators, washing machines, and other appliances, look for the Energy Star label. It will tell you which are the most efficient.

5. Reduce water waste.Saving water reduces carbon pollution, too. That's because it takes a lot of energy to pump, heat, and treat your water. So take shorter showers, turn off the tap while brushing your teeth, and switch to WaterSense-labeled fixtures and appliances. The EPA estimates that if just one out of every 100 American homes were retrofitted with water-efficient fixtures, about 100 million kilowatt-hours of electricity per year would be saved—avoiding 80,000 tons of global warming pollution.

6. Actually eat the food you buy—and make less of it meat.Approximately 10 percent of U.S. energy use goes into growing, processing, packaging, and shipping food—about 40 percent of which just winds up in the landfill. “If you’re wasting less food, you’re likely cutting down on energy consumption,” Haq says. And since livestock products are among the most resource-intensive to produce, eating meat-free meals can make a big difference, too.

7. Buy better bulbs.LED lightbulbs use up to 80 percent less energy than conventional incandescents. They’re also cheaper in the long run: A 10-watt LED that replaces your traditional 60-watt bulb will save you $125 over the lightbulb’s life.

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(b) is correct answer

(b) is correct answer

covalent character is will be maximum in Na3N.

as all others are more Ionic than Na3N

the right ans is option c.

option (c) aufbau principal is the right answer

option c is right answer

option c is the correct answer

option c is the right answer

option c is the right answer

The Pauli Exclusion Principle states that, in an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins.(1) option is correct

First carbon atom has sp hybridisation and Second carbon atom has sp2 hybridisation

can you show me the complete structure

The regions which are rich in reserves of Natural Gas Resources are: (a) Russia, U.K. and Norway in Europe. (b) Jaisalmer, Krishna-Godavari basin and Digboi Region in India.

There are number of advantages associated with exploiting resources with short term aims. These are increases gains associated with short aims as opposed to long term aims, much greater gains, capital rotation, quicker and better working of mind to deal with the resources and development of the nation as a whole. Also we would be saving the resources for our future generations.Inthe case of a long-time perspective in managing our resources, these resources will last for the generations to come. This management ensures uniform distribution among the people. It conserves the natural resources for many years and not just for a few years, as in the case of a short-term perspective in conserving natural resources.

than Define the atomic mass unit

Phenolphthalein indicator is a universal indicator. It turn colour less when added to hydrochloric acid. Neutralization reaction take place between acid and base.

Following steps can be followed to get determine the bond angle :

1. Draw Lewis dot structure of the given molecule and count the number of bonding and non-bonding electron groups (also known as Steric Number).

2.Use the Steric number and VSEPR theory to determine the geometry of the molecule (or electron domain geometries). {Refer to figure}

3.Use VSEPR shape to determine the angle between electron domain.

For example, for linear molecule there are two electron domain . Angle =360/(number of electron domain) =360/2 =180.

Formation of a π-bondoccurs by the sideways overlap of p-orbitals of two C-atoms.The molecularplanedoes not have any π-electron density since the p-orbitals are perpendicular to theplanecontaining theethenemolecule.Thenodal planein the π-bond of etheneis located in the molecularplane.

Formation of aπ-bond occurs by the sideways overlap of p-orbitals of two C-atoms.

The molecular plane does not have anyπ-electron density since the p-orbitals are perpendicular to the plane containing the ethene molecule.

The nodal plane in theπ-bond of ethene is located in the molecular plane.

again

1s^2 ,2s^2,20^6,3s^2

The atomic numberuniquelyidentifiesa chemical element. In an unchargedatom,the atomic numberis also equal to thenumberof electrons. thetotal numberof protons and neutrons in a nucleus.

protons In the nucleus