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3 years ago

Food and drink should be consumed when doing experiments in the lab or at home.

Chemistry

1 answer:

enot [183]3 years ago

7 0

Answer: False

Explanation:

Eating or drinking in the lab can, first and foremost, increase your risk of exposure to hazardous materials. Food or drink can leave a mess increasing the risks for contamination of your experiments and potentially attracting pests.

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Which change favors the products in this reversible reaction n2o4(g)+58 kj 2no2 (g)?

Ksenya-84 [330]

According to Le Chatelier's Principle, the position of equilibrium moves to counteract the change, the position of equilibrium will move so that the concentration of products of chemical reaction increase, if:

1) increase temperature, because this endothermic reaction.

2) increase concentration of reactant.

3) decrease pressure of the system, so reaction moves to direction where is more molecules.

7 0

4 years ago

Read 2 more answers

What is the weight of dark matter

Ostrovityanka [42]

Answer:

Knowing this, researchers from the University of Southern Denmark decided to investigate the size of these hypothetical hidden particles. According to the team, dark matter could weigh more than 10 billion billion (10^9) times more than a proton.

Explanation:

If this is true, a single dark matter particle could weigh about 1 microgram, which is about one-third the mass of a human cell (a typical human cell weighs about 3.5 micrograms), and right under the threshold for a particle to become a black hole.

3 0

3 years ago

Read 2 more answers

Based on the information given, classify each of the pure substances as elements or compounds, or indicate that no such classifi

Olenka [21]

Answer:

Analysis with an elaborate instrument indicates that:

Substance A contains two elements.

Compound

Substance B and substance C react to give a new substance D.

Insufficient information

Substance E decomposes upon heating to give substance F and substance G.

Compound

Heating substance H to 1000 °C causes no change.

Insufficient information

Substance I cannot be broken down into simpler substances by chemical means.

Element

Substance J cannot be broken down into simpler substances by physical means

Insufficient information

Explanation:

Important background:

Pure substances are elements or compounds.

Elements are formed by only one kind of atoms. They cannot be broken down into another substance by chemical or physical means. There are only 118 known elements; they are all listed in the periodic table.

Compounds have fixed chemical composition and are formed by two or more kind of atoms, chemically bonded. They can be broken down into different pure substances, either elements or other substances, only by chemical changes.

With tha information let's see every statement about the pure substances that should be classified as elements or compounds.

Substance A contains two elements: compound

Since, the pure substance contains two elements, it is not just and element by a compound. This is because a compound is a pure substance composed of two or more elements.

Substance B and substance C react to give a new substance D.: Insufficient information

Either two elements, one element and one compound, or two compounds may react to give a new substance, so you cannot assure what kind of pure substance B and C are.

For instance:

- two elements like hydrogen and oxygen reacto to give water (a compound)

- a compound like CH₂=CH₂ react with an element like Cl₂ to give CH₂Cl-CH₂Cl

Substance E decomposes upon heating to give substance F and substance G. : Compound

An element cannot be decomposed into two different substances, since the elements are composed by just one kind of atoms.

So, if the substance E decomposes into two different substances, F and G, E necessarily has to be a compound.

Heating substance H to 1000 ∘C causes no change. Insufficient information

The mere fact that a substance has not changed by heating at such extreme temperature cannot assure whether the substance is a compound or an element.

Some compounds are stable at very high temperatures. For instace, magnesium oxide, MgO, has a melting point of 2852°C, meaning that it will remain a a solid substance way beyond 1,000°C

Substance I cannot be broken down into simpler substances by chemical means. Element

Since an element is formed by one single kind of atoms, it cannot be broken down into simpler substances by chemical means; but a compose does, because it is formed by two or more different elements chemically bonded.

Substance J cannot be broken down into simpler substances by physical means: Insufficient information

The distintion between compounds and elements is based on chemical changes; the fact that physical changes do not change the substance does not tell anything about the fact that the substance is composed by one kind of elements or several elements chemical boonded.

Hence, physical means do not provide sufficient information to conclude about whether a substance is an element or a compound.

4 0

3 years ago

Dimethyl sulfoxide [(ch3)2so], also called dmso, is an important solvent that penetrates the skin, enabling it to be used as a t

Bas_tet [7]

The molecular formula of dimethyl sulfoxide is $(CH_{3})_{2}SO$ . Molar mass of dimethyl sulfoxide is 78.13 g/mol. Calculate number of moles as follows: