20 POINTS 2 QUESTIONS CAN YOU ANSWER THEM ???

2 answers:

6 0

The correct options are as follows:
1. A.
A synthesis reaction is a type of reaction in which two or more reactants combine together to form only one product. Synthesis reaction always release energy in form of light and heat, therefore, they are usually exothermic reactions. In the option given in A, nitrogen and nitrogen combine together to form ammonia; this is a synthesis reaction.
2. D
A radioactive half life refers to the amount of time it will take for half of an original radioactive isotope to decay.
In the question given above, the half life of the element is 1000. Thus, in 1000 years only half of the original amount will remain. In another 1000 years only 1/4 of the original amount will remain and in another 1000 years only 1/8 of the original amount will remain. Therefore, it will take 3 half lives before 1/8 of the original sample remain.<span />

kiruha [24]3 years ago

4 0

Answer:

the first one is a

the second one is d

Explanation:

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It is observed that the atoms of hydrogen in gas discharge tube emit radiations whose spectrum shows line characteristics (line

azamat

Answer: the line Spectra of hydrogen lies between the ultra-violet, visible light and infra-red of the electro magnetic spectrum

Explanation:

Electromagnetic radiation spans an wide range of wavelengths and frequencies. This range is called the electromagnetic spectrum. The electromagnetic spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The 7 regions includes; radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.

lower-energy radiation, such as radio waves, is expressed as frequency while microwaves, infrared, visible and UV light are usually expressed as wavelength and finally, higher-energy radiation such as X-rays and gamma rays, is expressed in terms of energy per photon.

Therefore, hydrogen lies between the ultra-violet, visible light and infra-red region of the electro magnetic spectrum.

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2 years ago

An evacuated 276 mL glass bulb weighs 129.6375 g. Filled with an unknown gas, the bulb weighs 130.0318 g. Calculate the gas dens

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Answer:

density=1.43 g/L

Explanation:

Since the density formula is density = mass / volume, we need to find out the mass of the gas and the volume is that of the container.

The mass of the gas is 130.0318 g-129.6375 g=0.3943 g

The gas volume is 276mL*(1L/1000mL) 0.276 L

density = mass / volume=0.3943g/0.276L

density =1.43g/L

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2 years ago

Covalent bonds form between hydrogen and oxygen atoms in a water molecule as a result of the:________.

Oliga [24]

Answer:

Explanation:

A covalent bond is said to be formed when two electrons are shared between two bonding atoms as in the formation of the water molecule.

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2 years ago

Whats the si unit chemist use to measure the amount of an element substance?

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The SI unit for the amount of substance present is the mole.

The mole is defined as the amount of substance that has the same amount of particles as there are atoms in 12 grams of carbon-12. Mathematically, the moles of a substance may be computed using:

moles present = mass of substance / molecular mass of substance

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2 years ago

Which of the following is not a reason why actual yield is less than theoretical yield?

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Your answer is B, conservation of mass

Recall that percent yield is given by: %Yeild = actual yeild/theoretical yeild x100

During experiments, there are errors made:

• uncertainty in measurements

• losses of reactants and products

• impurity in reactants

• losses during separation (e.g. filtration or purification)

• Some side reactions might also happen.

Among the given options, only conservation of mass does not contribute to a lower actual yield compared to the theoretical yield.

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2 years ago