Question 3

How much heat energy is needed to raise the temperature of 59.7g of cadmium from 25°C to 100°C? The specific heat of cadmium is

labwork [276]

Using the Fundamental Equation of Calorimetry, we have:

$Q=mc\Delta T \\ Q=59.7.0.231.(100-25) \\ \boxed {Q=1034.3025J}$

If you notice any mistake with my english, please know me, because I am not native.

7 0

3 years ago

An experiment applies heat to a substance and produces a gas that is a new and different substance. Choose the true statement.

sergejj [24]

Im a bit torn here, lets look at the definitions of physical and chemical changes:
physical change changes only the phase/state of a substance, but not what the substance is
chemical change is a chemical reaction where a new substance is formed and energy is given off or absorbed.
(it just started raining and it smells really nice out my window)

clearly, this cannot be just a physical reaction. i think i would be inclined to pick B. but C. could have merit as an answer too. sorry for the ambiguity x

7 0

3 years ago

In an aqueous solution, 42% of a substance dissociates to release hydronium ions. Which of the following statements is true for

const2013 [10]

Answer: The statement it is a weak acid is true for the substance.

Explanation:

An acid that dissociates completely when dissolved in water to give hydrogen $(H^{+})$ or hydronium $(H_{3}O^{+})$ ions is called a strong acid.

For example, HCl is a strong acid.

$HCl + H_{2}O \rightarrow H_{3}O^{+} + Cl^{-}$

An acid that dissociates partially or weakly when dissolved in water to given hydrogen or hydronium ions is called a weak acid.

For example, $CH_{3}COOH$ is a weak acid.

$CH_{3}COOH \rightleftharpoons CH_{3}COO^{-} + H_{3}O^{+}$

A strong base is a base which when dissolved in water then it dissociates completely to give hydroxide ions.

For example, NaOH is a strong acid.

A weak base is a base which when dissolved in water then it dissociates partially or weakly to give hydroxide ions.

For example, $NH_{3}$ is a weak base.

Hence, in an aqueous solution where 42% of a substance dissociates to release hydronium ions shows that the dissociation is less than 50%. This means that substance is dissociating weakly so, it is a weak acid.

Thus, we can conclude that the statement it is a weak acid is true for the substance.

5 0

3 years ago

How do i solve number 36?

tresset_1 [31]

To cut this short and for your understanding, ionic bond is formed between metals (mostly right column in periodic table). Covalent bond is formed between non-metals (mostly left column in periodic table). So polar covalent is also a covalent bond but it is polar, which means the shape of molecules are not symmetrical hence maybe an atom in a molecule has most of the electron attracted to it causing itself to be partial negative (since electron are negatively charged) and the other atom has its electron being attracted by others became partial positive. Polar covalent can also be when H atom is binding either to F, O or N (also known as hydrogen bond).

6 0

2 years ago

What do you think happens to the bonds between atoms when substances melt?

Eduardwww [97]

Answer:

As a substance melts, and goes from a solid to a liquid state, the kinetic energy of the molecules increases, and the molecules move faster, and they separate further and further away from each other. The intermolecluar forces holding the molecules together become weaker. This is why a liquid can take fill the shape of its container, whereas a solid has a fixed shape.

Explanation:

take your notes man

6 0

3 years ago