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4 years ago

Planet one two elements are?

Chemistry

2 answers:

AnnyKZ [126]4 years ago

5 0

Answer:

75% hydrogen 25% helium

Explanation:

kherson [118]4 years ago

3 0

Yes it is 75% hydrogen and 25% helium

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What is the molar mass of Ca(NO3)2

artcher [175]

Ca=40
N=14
O=16
Ca=40
N=14x2=28
O=6x16=96
molar mass=40+28+96
molar mass=164g/mol

7 0

3 years ago

Read 2 more answers

PbO2 + 4HCl --- PbCl2 + Cl2 + 2H2O who buys electrons and who loses electrons?

SIZIF [17.4K]

Answer: Electrons are taken up by $PbO_2$ and they are lost by $HCl$

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously. It is also called the reaction where the exchange of electrons takes place.

An oxidation reaction is defined as the reaction in which a chemical species loses electrons takes place. In this reaction, the oxidation state of a substance gets increased.

A reduction reaction is defined as the reaction in which a chemical species gains electrons takes place. In this reaction, the oxidation state of a substance gets reduced.

For the given chemical reaction:

$PbO_2+4HCl\rightarrow PbCl_2+Cl_2+2H_2O$

The half-reactions for this redox rection follows:

Oxidation half-reaction: $2HCl\rightarrow ClO_2 + 2e^-$

Reduction half-reaction: $PbO_2+2e^-\rightarrow PbCl_2$

Hence, electrons are taken up by $PbO_2$ and they are lost by $HCl$

8 0

3 years ago

Which of the following sentences represents a physical change? sugar dissolves in coffee iron rusts gasoline burns in an engine

MAXImum [283]

Answer:

Physical changes example is sugar dissolves in coffee
Chemical changes examples are iron rusts, gasoline burns in an engine and a candle burns.

Explanation.

Physical changes depend on only physical state, not on composition, which can be separated by physical means while chemical changes depend on composition and only separated by chemical ways.
As in case of iron rusting, gasoline and candle burn are cases chemical changes bcz they convert into another substance whose composition is different from other as compare to sugar which has same composition in coffee ,only state is changed from solid to liquid.

6 0

3 years ago

Read 2 more answers

How are the movement of tectonic plates and volcanoes related ?

ivann1987 [24]

The earth’s plates sliding against each other and moving under each other causes earthquakes. When plates move apart, magma comes up, thus forming a volcano.

4 0

4 years ago

Read 2 more answers

A chemist prepares a solution of aluminum sulfate (Al2(SO4) by weighing out 116.0 g of aluminum sulfate into a 450. mL volumetri

trasher [3.6K]

Answer:

0.0733 mol /dL

Explanation:

Mole -

Moles is denoted by given mass divided by the molecular mass ,

Hence ,

n = w / m

n = moles ,

w = given mass ,

m = molecular mass .

From the information of the question ,

w = 116.0 g

As we know, molecular mass of aluminum sulfate ,

m = 342.15 g/mol

n = w / m

n = 116.0 g / 342.15 g/mol = 0.33 mol

Molarity -

Molarity of a substance , is the number of moles present in a liter of solution .

M = n / V

M = molarity

V = volume of solution in liter ,

n = moles of solute ,

The unit is mol / L ,

Hence , from the question, the value of molarity is asked ,

From the information of the question ,

V = 450 mL ,

Since,

1 mL = 0.01 dL

As, the unit asked in the question is in dL,

V = 4.5 dL

n = 0.33 mol ( as calculated above )

Using the above formula ,

M = n / V

M = 0.33 mol / 4.5 dL

M = 0.0733 mol /dL

M =

5 0

4 years ago