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4 years ago

Please help! I’m stuck on this. (Giving brainliest answer to whoever answers everything) please and thank you!

Chemistry

1 answer:

Schach [20]4 years ago

3 0

Answer:

Explanation:

1 : apple sliced : the apple was cut into smaller peices : physical change

2 : smashed apple : the apple became a mush : physical change

3 : paper burned : the paper became ash : chemical change

4 : glow stick snapped : the glow stick started glowing : chemical change

5 : apple being burned : the apple became discoloured and turned coal-like : chemical change

_____

2. it does not alter the chemical make up of the apple

3. because it changes to a new substance entirely, changing the chemical make up of the paper to make it something new

4. smashing the apple, because you mash up the apple with your teeth in your mouth

5. The apple being burned is being chemically broken down to form a new substance, the same way your stomach digests food to break down and use for other reasons.

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Describe how the properties of elements in the same group differ to the properties of elements in the same period

Fofino [41]

Answer:

(a) (i) All the elements of a group have similar chemical properties because they have same no. of valence electrons in their outermost shell. (ii) All the elements of a period have different chemical properties because they have different no. of valence electrons in their atoms.

5 0

3 years ago

A student titrated a solution containing 3.7066 g of an unknown Diprotic acid to the end point using 28.94 ml of 0.3021 M KOH so

uranmaximum [27]

Answer:

Molar mass of the diprotic acid is 424 grams

Explanation:

[hint: diprotic acid only contains 2 hydrogen protons]

Ionic equation:

${ \bf{2OH { }^{ - } _{(aq)} + 2H { }^{ + } _{(aq)}→ 2H _{2} O _{(l)} }}$

first, we get moles of potassium hydroxide in 28.94 ml :

${ \sf{1 \: l \: of \: KOH \: contains \: 0.3021 \: moles}} \\ { \sf{0.02894 \: l \: of \: KOH \: contain \: (0.02894 \times 0.3021) \: moles}} \\ { \underline{ = 0.008743 \: moles}}$

since mole ratio of diprotic acid : base is 2 : 2, moles are the same.

Therefore, moles of acid that reacted are 0.008743 moles.

${ \sf{0.008743 \: moles \: of \: acid \: weigh \: 3.7066 \: g}} \\ { \sf{1 \: mole \: of \: acid \: weighs \: ( \frac{1 \times 3.7066}{0.008743}) \: g }} \\ = { \underline{423.95 \: g \approx424 \: grams}}$

for the molar mass:

8 0

3 years ago

11) What is the volume of 4.92 grams of hydrogen gas at STP? (Show the work using dimensional analysis)

lorasvet [3.4K]

Answer:

The volume of 4.92 grams of hydrogen gas at STP is 9.105 litter.

Explanation:

We know that, the molecular weight of hydrogen gas $(H_{2} )$ = $1\times 2 = 2$ .

Moles of hydrogen gas = $\frac{weight}{molecular weight} = \frac{4.92}{2} = 2.46$ moles.

At STP, 1 mole of hydrogen gas = occupies 22.4 litter

So, 2.46 mole of hydrogen gas = occupies $\frac{22.4}{2.46} = 9.105$ litter.

Hence, the volume of 2.46 grams of hydrogen gas at STP is 9.105 litter.

4 0

3 years ago

If 46.3 grams of acetylene are required to run a carbide lamp for 8 hours, how many moles of water are required

attashe74 [19]

Answer:

1.78 mol

Explanation:

Step 1: Write the balanced equation

CaC₂ + H₂O ⇒ C₂H₂ + CaO

Step 2: Calculate the moles corresponding to 46.3 g of C₂H₂

The molar mass of C₂H₂ is 26.04 g/mol.

46.3 g × 1 mol/26.04 g = 1.78 mol

Step 3: Calculate the moles of H₂O required to form 1.78 moles of C₂H₂.

The molar ratio of H₂O to C₂H₂ is 1:1. The moles of H₂O required are 1/1 × 1.78 mol = 1.78 mol.

7 0

3 years ago

Look at the diagram of an electrolytic cell below.

Ipatiy [6.2K]

The cathode is Y

<h3>Further explanation</h3>

Electrolysis uses electrical energy to carry out redox reactions that are not spontaneous.

The ions in the solution flowing electrically will move towards to opposite charge of the electrode

The electrolysis material is an electrolyte which can be a solution or a melt.

In positive pole electrolysis cells - the anode is the site of the oxidation reaction, while the negative pole - the cathode is the reduction reaction site.

The result of the reaction in the anode is based on a substance that easily oxidized while the reaction in the cathode is based on a substance that easily reduced.

Electrons (electricity) enter an electrolysis cell through the negative pole (cathode)

The negative ion from the solution will move towards the positive electrode and release the electrons around the positive electrode (oxidation) and the electrons flow to the negative pole

Whereas around the negative electrode, there is electron binding and a reduction reaction occurs

So if we see the picture the cathode is Y

<h3>Learn more</h3><h3>reaction related to electrochemistry brainly.com/question/3461108</h3>

<h3>Answer details </h3>

Grade: Senior High School

Subject: Chemistry

Chapter: Electrochemistry

Keywords: cathode, anode, oxidation, reduction, negative pole, electrode

8 0

4 years ago