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3 years ago

Science 7 Grade 7. Can anyone please help me answer these science questions?

Chemistry

2 answers:

masha68 [24]3 years ago

6 0

A cellphone battery is a electrical energy
and a piston in an engine is an thermal energy

NARA [144]3 years ago

4 0

Thermal expansion in a balloon occurs because when the balloon is heated up, the gas molecules will move faster and in greater distance so when if they move faster then they will hit the wall with greater force, will result to expansion.

conduction, convection and radiation are the ways that thermal energy is transferred.

a cellphone battery is an electrical energy, then piston in an engine is mechanical energy

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The formula mass of HC2H302 is 1. 59 2. 60 3. 72 4. 80

Savatey [412]

Answer:

Explanation:

The formula of the compound is given as:

HC₂H₃O₂

To find the formula mass we sum up the atomic masses of the component elements;

Atomic mass:

H = 1

C = 12

O = 16

HC₂H₃O₂ = 1 + 2(12) + 3(1) + 2(16)

= 1 + 24 + 3 + 32

= 60

4 0

3 years ago

Draw a mechanism for the reaction of methanol with sodium amide. Draw any necessary curved arrows. Show the products of the reac

Usimov [2.4K]

Answer:

Please find equations in the attachment file.

Explanation:

3 0

3 years ago

Consider the reaction: 2BrF3(g) --> Br2(g) + 3F2(g)

riadik2000 [5.3K]

Answer : The entropy change of reaction for 1.62 moles of $BrF_3$ reacts at standard condition is 217.68 J/K

Explanation :

The given balanced reaction is,

$2BrF_3(g)\rightarrow Br_2(g)+3F_2(g)$

The expression used for entropy change of reaction $(\Delta S^o)$ is:

$\Delta S^o=S_f_{product}-S_f_{reactant}$

$\Delta S^o=[n_{Br_2}\times \Delta S_f^0_{(Br_2)}+n_{F_2}\times \Delta S_f^0_{(F_2)}]-[n_{BrF_3}\times \Delta S_f^0_{(BrF_3)}]$

where,

$\Delta S^o$ = entropy change of reaction = ?

n = number of moles

$\Delta S_f^0$ = standard entropy of formation

$\Delta S_f^0_{(Br_2)}$ = 245.463 J/mol.K

$\Delta S_f^0_{(F_2)}$ = 202.78 J/mol.K

$\Delta S_f^0_{(BrF_3)}$ = 292.53 J/mol.K

Now put all the given values in this expression, we get:

$\Delta S^o=[1mole\times (245.463J/K.mole)+3mole\times (202.78J/K.mole)}]-[2mole\times (292.53J/K.mole)]$

$\Delta S^o=268.74J/K$

Now we have to calculate the entropy change of reaction for 1.62 moles of $BrF_3$ reacts at standard condition.

From the reaction we conclude that,

As, 2 moles of $BrF_3$ has entropy change = 268.74 J/K

So, 1.62 moles of $BrF_3$ has entropy change = $\frac{1.62}{2}\times 268.74=217.68J/K$

Therefore, the entropy change of reaction for 1.62 moles of $BrF_3$ reacts at standard condition is 217.68 J/K

3 0

4 years ago

What happens when a solid melt completely

Likurg_2 [28]

It becomes a liquid lol

3 0

3 years ago

7. Write a balanced chemical equation for the following reactions and label what type of reaction it is. (3 points)

slamgirl [31]

(A) Naoh + Hno3 == Nano3 + h20.
and it is acid based reaction.
(B) H + Br == Hbr. it is synthesis reaction
and it should be hydrogen gas with bromine gas if that was question then
H2 + Br2 == 2Hbr
(c) 3Agno3 + Alcl3 == Al (No3)3 + 3Agcl
it is double displacement. and we right the polyatomic ion in bracket that’s why no3 is in bracket.
please let me know if you need something

5 0

3 years ago

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