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3 years ago

Which of these definitions BEST describes a solution?

Chemistry

1 answer:

Damm [24]3 years ago

6 0

Answer:

C. A combination of 3 or more different substances that do not chemically combine

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What is the change in internal energy (ΔΕ) of a system when 5 kJ of work is done on the system while it releases 13 kJ of energy

meriva

The change in internal energy (ΔΕ) of a system : -8 kJ

<h3>Further explanation </h3>

The laws of thermodynamics 1 state that: energy can be changed but cannot be destroyed or created

The equation is:

$\tt \Delta U=Q+W$

Energy owned by the system is expressed as internal energy (U)

This internal energy can change if it absorbs heat Q (U> 0), or releases heat (U <0). Or the internal energy can change if the system does work or accepts work (W)

The sign rules for heat and work are set as follows:

• The system receives heat, Q +

• The system releases heat, Q -

• The system does work, W -

• the system accepts work, W +

5 kJ of work is done on the system : W = +5 kJ

releases 13 kJ of energy to the surroundings : Q = -13 kJ

$\tt \Delta E=-13+5=-8~kJ$

6 0

3 years ago

Iodine 131, cesium 137, and strontium 90 are all considered isotopes. What are isotopes?

Nitella [24]

Answer:

Isotopes are variants of an element, where the number of neutrons is different but its number of protons stay the same.

Explanation:

If the number of protons had changed then it would just be a different element.

Electron number changing simply adds charge to the atom, and doesn't change it or anything.

PLS GIVE BRAINLIEST

3 0

3 years ago

Read 2 more answers

When a 3.00 g 3.00 g sample of KBr KBr is dissolved in water in a calorimeter that has a total heat capacity of 1.36 kJ ⋅ K − 1

cupoosta [38]

Answer:

Molar heat of solution of KBr is 20.0kJ/mol

Explanation:

Molar heat of solution is defined as the energy released (negative) or absorbed (Positive) per mole of solute being dissolved in solvent.

The dissolution of KBr is:

KBr → K⁺ + Br⁻

In the calorimeter, the temperature decreases 0.370K, that means the solution absorbes energy in this process. The energy is:

q = 1.36kJK⁻¹ × 0.370K

q = 0.5032kJ

Moles of KBr in 3.00g are:

3.00g × (1mol / 119g) = 0.0252moles

Thus, molar heat of solution of KBr is:

0.5032kJ / 0.0252moles = <em>20.0kJ/mol</em>

3 0

4 years ago

Does heating a cup of water allow it to dissolve more sugar? Temperature of the water is measured in degrees centigrade. Amount

Alexeev081 [22]

Answer:

Yes

Explanation:

Yes heating water allows it to dissolve more Sugars because the molecular distance increases and this distance can be covered by more sugar. In the given question, The independent variable would be the temperature of water.

Since to whatever temperature the water boils at the boiling temperature of does not change remains hundred degree. Rest all the variables can vary the weight of the amount of sugar with the variable in the temperature of Boiling of water to remain constant.

6 0

3 years ago

Which organisms in this food web are carnivores? Select the two correct

LUCKY_DIMON [66]

The two correct options are Poison dart frog and Boa constrictor. Both these organisms are pure carnivores which are also known as pure meat eaters in the food web. Carnivores are organisms in the food chain that only meat-eaters and never take any type of vegetation in their diet.

Explanation:

A Poison dart frog purely survives on meat (meat- eater).
Long sticky tongues are used to catch their prey such as ants, flies, insects.
Since they produce high toxin levels, it has very few predators in the wild.
Boa constrictor is also an organism that eats only meat.
While they are young they eat prey like rats, squirrels and mice.
The type of attack used by a boa constrictor is an ambush attack type. It attacks its preys using the surprise factor.

6 0

4 years ago