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3 years ago

How many periods does the modern periodic table have?

Chemistry

1 answer:

dusya [7]3 years ago

8 0

There are 7 periods in the modern periodic table

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Which of the following would decrease current flow in a circuit made originally from a 1.5 volt battery, a loop of wire and a sw

Paladinen [302]

Just took the test

It's B = original battery, thinner wire

3 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

Balance Reaction K(s) + H2O(l) —> KOH(aq) + H2

Wewaii [24]

Answer:

Chemistry is a branch of science that involves the study of the composition, structure and properties of matter. Often known as the central science, it is a creative discipline chiefly concerned with atomic and molecular structure and its change, for instance through chemical reactions.Explanation:Chemistry is a branch of science that involves the study of the composition, structure and properties of matter. Often known as the central science, it is a creative discipline chiefly concerned with atomic and molecular structure and its change, for instance through chemical reactions.

4 0

3 years ago

Filtering air to remove dust and pollen is it chemical or physical change

Cerrena [4.2K]

Answer:

Physical Change

Explanation:

Because the filter is removeing the dust by having the air go though a thin material.

Hope it helps!

3 0

3 years ago

When cyclopentane undergo free-radical substitution with bromine (Br2 /Heat) the product:

Artemon [7]

Explanation:

b. Bromo cyclopentane + HBr

4 0

3 years ago