All the ways scientists do investigations

How many lines does a starfish have in symmetry

Ahat [919]

A starfish has five equal arms, so a starfish would have 5 lines of symmetry. Hope this helps!

5 0

3 years ago

The strength of a covalent bond depends upon the size of the atoms and the bond order. In general short bonds are strong bonds.1

Oksana_A [137]

Answer:

Bond energy of (A) C≡C > (B) C=C

and, (C) C=N > (D) C-N

Explanation:

Bond energy refers to the amount of energy required to break a bond or the energy released when a bond is formed. Bond energy of a covalent bond suggests the bond strength of the chemical bond and depends on the bond length and bond order of the chemical bond.

The bond energy of a chemical bond increases with the bond order and decreases with the bond length. As, length of a bond decreases with increase in the bond order.

First pair: (A) C≡C (B) C=C

The bond order of C≡C - 3, the bond order of C=C - 2

Since the bond order: C≡C > C=C

Bond length: C≡C < C=C

Therefore, bond energy of (A) C≡C > (B) C=C

Second pair: (C) C=N (D) C-N

The bond order of C=N - 2, the bond order of C-N - 1

Since the bond order: C=N > C-N

Bond length: C=N < C-N

Therefore, bond energy of (C) C=N > (D) C-N

8 0

3 years ago

What volume of CH4(g), measured at 25oC and 745 Torr, must be burned in excess oxygen to release 1.00 x 106 kJ of heat to the su

anastassius [24]

Answer:

$V=27992L=28.00m^3$

Explanation:

Hello,

In this case, the combustion of methane is shown below:

$CH_4+2O_2\rightarrow CO_2+2H_2O$

And has a heat of combustion of −890.8 kJ/mol, for which the burnt moles are:

$n_{CH_4}=\frac{-1.00x10^6kJ}{-890.8kJ/mol}= 1122.6molCH_4$

Whereas is consider the total released heat to the surroundings (negative as it is exiting heat) and the aforementioned heat of combustion. Then, by using the ideal gas equation, we are able to compute the volume at 25 °C (298K) and 745 torr (0.98 atm) that must be measured:

$PV=nRT\\\\V=\frac{nRT}{P}=\frac{1122.6mol*0.082\frac{atm*L}{mol*K}*298K}{0.98atm}\\\\V=27992L=28.00m^3$

Best regards.

8 0

3 years ago

Why were they put into water before we tested them?

klasskru [66]

explain the question your asking

7 0

3 years ago

Read 2 more answers

A series of chemicals were added to some AgNO3(aq). NaCl(aq) was added first to the silver nitrate solution to produce a precipi

OLEGan [10]

Answer:

First, precipitate of AgCl is formed. Second, a soluble complex of silver and ammonia is formed. Third, AgCl is reproduced due to disappearance of ammonia complex in presence of $HNO_{3}$ .

Explanation:

In presence of NaCl, $AgNO_{3}$ forms an insoluble precipitate of AgCl.

Reaction: $Ag^{+}(aq.)+Cl^{-}(aq.)\rightarrow AgCl(s)$

In presence of $NH_{3}$ , AgCl gets dissolved into solution due to formation of soluble $[Ag(NH_{3})_{2}]^{+}$ complex.

Reaction: $AgCl(s)+2NH_{3}(aq.)\rightarrow [Ag(NH_{3})_{2}]^{+}(aq.)+ Cl^{-}(aq.)$

In presence of $HNO_{3}$ , $[Ag(NH_{3})_{2}]^{+}$ complex gets destroyed and free $Cl^{-}$ again reacts with free $Ag^{+}$ to produce insoluble AgCl

Reaction: $[Ag(NH_{3})_{2}]^{+}(aq.)+2H^{+}(aq.)+Cl^{-}(aq.)\rightarrow AgCl(s)+2NH_{4}^{+}(aq.)$

4 0

3 years ago