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3 years ago

HELP PLEASE , I NEED A A ON THE TEST I’ll give brain

Chemistry

2 answers:

goldenfox [79]3 years ago

8 0

The answer to this is c! I called it

iragen [17]3 years ago

6 0

Answer:

left

Explanation:

8 has the strongest force

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a nuclide of 64/29 cu absorbs a positron. witch is the resulting atom? (A) 65/29Cu (B) 63/29 CU (C) 64/28Ni (D) 64/30 Zn

Nesterboy [21]

Answer : Option D) $Zn^{64}_{30}$

Explanation : When a positron is getting absorbed it means it will be $e^{+1}_{0}$ so, the $Cu^{64}_{29}$ will get converted;

So, the whole reaction will be;

$Cu^{64}_{29}$ + $e^{+1}_{0}$ ----> $Zn^{64}_{30}$ .

This will convert the whole element of Cu will get changed into Zn. As, it absorbs by the positron, the atomic number gets increased from 29 to 30.

4 0

3 years ago

Aluminum metal and manganese (IV) oxide react to produce aluminum oxide and manganese metal. What mass of manganese (IV) oxide r

gayaneshka [121]

Answer: 1.77 kg of manganese (IV) oxide reacts to produce 1.12kg of manganese metal.

Explanation:

The balanced chemical equation is:

$4Al+3MnO_2\rightarrow 2Al_2O_3+3Mn$

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

moles of manganese = $\frac{1.12\times 1000g}{55g/mol}=20.4mol$

According to stoichiometry :

3 moles of $Mn$ is produced by = 3 moles of $MnO_2$

Thus 20.4 moles of $Mn$ is produced by = $\frac{3}{3}\times 20.4=20.4moles$ of $MnO_2$

Mass of $MnO_2=moles\times {\text {Molar mass}}=20.4moles\times 86.9g/mol=1773g=1.773kg$ (1kg=1000g)

Thus 1.77 kg of manganese (IV) oxide reacts to produce 1.12kg of manganese metal.

6 0

3 years ago

Identify the chemical reactions as endothermic, exothermic, or neither. An egg cooking: A candle burning: Plaster and water comb

lianna [129]

Answer :

An egg cooking is an endothermic reaction.

A candle burning and Plaster & water combining and becoming warm are exothermic reaction.

Salt being added to water, with no change in temperature neither endothermic nor exothermic reaction.

Explanation :

Endothermic reaction : It is a type of reaction in which energy is absorbed in the form of heat from the surroundings.

Exothermic reaction : It is a type of reaction in which energy is released in the form of heat from the system.

An egg cooking : In this process, the energy is absorbed in the form of heat.

A candle burning and Plaster & water combining and becoming warm : In both the process, the energy is released in the form of heat.

Salt being added to water, with no change in temperature : In this process, neither energy released nor absorbed.

5 0

3 years ago

Read 2 more answers

Help please I really really need it now

postnew [5]

1. A 2. B 5. B this is all I know hope it helps

5 0

2 years ago

A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the

horrorfan [7]

Answer : (C) Hafnium is the most likely identity of the given substance.

Solution : Given,

Mass of given substance (m) = 46.9 g

Volume of given substance (V) = 3.5 $Cm^{3}$

First, find the Density of given substance.

Formula used :

$Density=\frac{\text{Mass of given substance}}{\text{Voume of given substance}}$

Now,put all the values in this formula, we get

$Density=\frac{46.9 g}{3.5 Cm^{3} }$ = 13.4 g/ $Cm^{3}$

So, we conclude that the density of given substance (13.4 g/ $Cm^{3}$ ) is approximately equal to the density of Mercury and Hafnium (13.53 and 13.31 g/ $Cm^{3}$ respectively).

According to the question the substance is solid at room temperature but Mercury is liquid at room temperature. So, Mercury is not identical to the given substance.

Another element i.e, Hafnium is the element whose density is approximately equal to the given substance and also solid at room temperature. And we know that the melting point of solid is high.

So, Hafnium is the most likely element which is the identity of the given substance.

3 0

3 years ago

Read 2 more answers