________ is the enthalpy change when 1 mole of a substance is formed from its elements under standard conditions.

What information would you find on a WHIMIS label?

Nady [450]

Answer/explanation:

Product identifier – the brand name, chemical name, common name, generic name or trade name of the hazardous product.
Initial supplier identifier – the name, address and telephone number of either the Canadian manufacturer or the Canadian importer.

8 0

2 years ago

What are heterogeneous and homogeneous?

vichka [17]

A homogeneous mixture has the same uniform appearance and composition throughout.
A heterogeneous mixture consists of visibly different substances or phases. The three phases or states of matter are gas, liquid, and solid.
A homogeneous mixture has the same uniform appearance and composition throughout. Many homogeneous mixtures are commonly referred to as solutions. A heterogeneous mixture consists of visibly different substances or phases.

3 0

2 years ago

What temperature will the water reach when 10.1 g CaO is dropped into a coffee cup containing 157 g H2O at 18.0°C if the followi

Zepler [3.9K]

Answer:

Final temperature attained by water = 34.6°C

Explanation:

The reaction of CaO and H₂O is an <em>exothermic reaction</em>. The equation of reaction is given below:

CaO + H₂O ----> Ca(OH)₂

The quantity of heat given off, ΔH°rxn = 64.8KJ/mol = 64800J/mol

Number of moles of CaO = mass/molar mass, where molar mass of Ca0 = 56g/mol, mass of CaO = 10.1g

Number of moles of CaO = 10.1g/56g/mol =0.179moles

Quantity of heat given off by 0.179 moles = 64800 *0.179 = 11599.2J/mol

Using the formula, <em>Quantity of heat, q = mass * specific heat capacity * temperature rise.</em>

mass of mixture = (10.1 + 157)g = 167.1g, Initial temperature = 18.0°C

Final temperature(T₂) - Initial temperature(T₁) = Temperature rise

11599.2J/mol = 167.1g * 4.18J/g·°C * ( T₂ - 18.0°C)

11599.2 = 698.478T₂ - 12572.604

11599.2 + 12572.604 = 698.478T₂

698.478T₂ = 24171.804

T₂ = 34.6°C

Therefore, final temperature attained by water = 34.6°C

6 0

3 years ago

Difference between reactants and products.

Arisa [49]

Answer:

a reactant is a substance that is at the beginning of a Chemical reaction while a product is a substance that is present at the end of a chemical reaction.in other words a reactant is a substance used up in a chemical reaction to produce something while a reactant is what is produced after a chemical reaction.

I hope this helps

5 0

3 years ago

When temperture changes matter undergo this. that is shift one form to another

dsp73

Answer:All matter can move from one state to another. It may require extreme temperatures or extreme pressures, but it can be done. Sometimes a substance doesn't want to change states. You have to use all of your tricks when that happens. To create a solid, you might have to decrease the temperature by a huge amount and then add pressure. For example, oxygen (O2) will solidify at -361.8 degrees Fahrenheit (-218.8 degrees Celsius) at standard pressure. However, it will freeze at warmer temperatures when the pressure is increased.

Some of you know about liquid nitrogen (N2). It is nitrogen from the atmosphere in a liquid form and it has to be super cold to stay a liquid. What if you wanted to turn it into a solid but couldn't make it cold enough to solidify? You could increase the pressure in a sealed chamber. Eventually you would reach a point where the liquid became a solid. If you have liquid water (H2O) at room temperature and you wanted water vapor (gas), you could use a combination of high temperatures or low pressures to solve your problem.

Points of Change

Phase Changes: Pressure and temperature define the state of matter for water.Phase changes happen when you reach certain special points. Sometimes a liquid wants to become a solid. Scientists use something called a freezing point or melting point to measure the temperature at which a liquid turns into a solid. There are physical effects that can change the melting point. Pressure is one of those effects. When the pressure surrounding a substance increases, the freezing point and other special points also go up. It is easier to keep things solid when they are under greater pressure.

Generally, solids are more dense than liquids because their molecules are closer together. The freezing process compacts the molecules into a smaller space.

There are always exceptions in science. Water is special on many levels. It has more space between its molecules when it is frozen. The molecules organize in a specific arrangement that takes up more space than when they are all loosey-goosey in the liquid state. Because the same number of molecules take up more space, solid water is less dense than liquid water. There are many other types of molecular organizations in solid water than we can talk about here.

CHEMISTRY TERM PHASE CHANGE

Fusion/Melting

Freezing

Vaporization/Boiling

Condensation

Sublimation

Deposition

Solid to a Liquid

Liquid to a Solid

Liquid to a Gas

Gas to a Liquid

Solid to a Gas

Gas to a Solid

Explanation:

7 0

2 years ago