Can someone please name a project I can do for my science fair for 7th grade I need a easy one

Which of the following is a property of carbon atoms?

marusya05 [52]

Answer:

B. They can for covalent bonds with other atoms.

Explanation:

Carbon = King of the elements on the periodic table

For its proclivity to form stable covalent bonds with multivalent atoms.

5 0

3 years ago

Read 2 more answers

Based on the chemical equation, use the drop-down menu to choose the coefficients that will balance the chemical equation: ()zn

kompoz [17]

Based on the chemical equation, to balance the given equation we should use 2 as a coefficients of HCl on reacatnt side of the reaction.

<h3>What is balanced equation?</h3>

Balanced chemical equations are those equation in which each entities are present in same amount on reactant side as well as on the product side of the chemical reaction.

Given chemical reaction is:

Zn + HCl → ZnCl₂ + H₂

In the above reaction equation is not balanced as number of chlorine and hydrogen atoms are not equal on both sides, so balanced equation will be:

Zn + 2HCl → ZnCl₂ + H₂

Hence we add 2 as a coefficient of HCl to balance the equation.

To know more about balance equation, visit the below link:

brainly.com/question/15355912

8 0

2 years ago

Please help I really appreciate it thank you ❤️

Feliz [49]

II. sulfur (S) and carbon (C)

and

III. fluorine (F) and oxygen (O)

will form covalent bonds, so the answer will be:

e. II and III

Explanation:

To know is what type of bond is formed between atoms we need to look at the electronegativity difference between the atoms.

If the electronegativity difference is less than 0.4 there is a nonpolar covalent bond.

If the electronegativity difference is between 0.4 and 1.8 there is a polar covalent bond. (if is a metal involved we consider the bond to be ionic)

If the electronegativity difference is greater then 1.8 there is an ionic bond.

We have the following cases:

I. lithium (Li) and sulfur (S)

electronegativity difference = 2.5 (S) - 1 (Li) = 1.5 but because there is a metal involved the bond will be ionic

II. sulfur (S) and carbon (C)

electronegativity difference = 2.5 (S) - 2.5 (C) = 0 so the bond will be nonpolar covalent

III. fluorine (F) and oxygen (O)

electronegativity difference = 4 (F) - 3.5 (O) = 0.5 so the bond will be polar covalent bond.

Learn more about:

covalent and ionic bonds

brainly.com/question/1802971

#learnwithBrainly

3 0

4 years ago

The gas-phase reaction follows an elementary rate law and is to be carried out first in a PFR and then in a separate experiment

astraxan [27]

Answer:

The activation energy is $=8.1\,kcal\,mol^{-1}$

Explanation:

The gas phase reaction is as follows.

$A \rightarrow B+C$

The rate law of the reaction is as follows.

$-r_{A}=kC_{A}$

The reaction is carried out first in the plug flow reactor with feed as pure reactant.

From the given,

Volume "V" = $10dm^{3}$

Temperature "T" = 300 K

Volumetric flow rate of the reaction $v_{o}=5dm^{3}s$

Conversion of the reaction "X" = 0.8

The rate constant of the reaction can be calculate by the following formua.

$V= \frac{v_{0}}{k}[(1+\epsilon )ln(\frac{1}{1-X}-\epsilon X)]$

Rearrange the formula is as follows.

$k= \frac{v_{0}}{V}[(1+\epsilon )ln(\frac{1}{1-X}-\epsilon X)]............(1)$

The feed has Pure A, mole fraction of A in feed $y_{A_{o}}$ is 1.

$\epsilon =y_{A_{o}}\delta$

$\delta$ = change in total number of moles per mole of A reacte.

$=1(2-1)=1$

Substitute the all given values in equation (1)

$k=\frac{5m^{3}/s}{10dm^{3}}[(1+1)ln \frac{1}{1-0.8}-1 \times 0.8] = 1.2s^{-1}$

Therefore, the rate constant in case of the plug flow reacor at 300K is $1.2s^{-1}$

The rate constant in case of the CSTR can be calculated by using the formula.

$\frac{V}{v_{0}}= \frac{X(1+\epsilon X)}{k(1-X)}.............(2)$

The feed has 50% A and 50% inerts.

Hence, the mole fraction of A in feed $y_{A_{o}}$ is 0.5

$\epsilon =y_{A_{o}}\delta$

$\delta$ = change in total number of moles per mole of A reacted.

$=0.5(2-1)=0.5$

Substitute the all values in formula (2)

$\frac{10dm^{3}}{5dm^{3}}=\frac{0.8(1+0.5(0.8))}{k(1-0.8)}=2.8s^{-1}$

Therefore, the rate constant in case of CSTR comes out to be $2.8s^{-1}$

The activation energy of the reaction can be calculated by using formula

$k(T_{2})=k(T_{1})exp[\frac{E}{R}(\frac{1}{T_{1}}-\frac{1}{T_{2}})]$

In the above reaction rate constant at the two different temperatures.

Rearrange the above formula is as follows.

$E= R \times(\frac{T_{1}T_{2}}{T_{1}-T_{2}})ln\frac{k(T_{2})}{k(T_{1})}$

Substitute the all values.

$=1.987cal/molK(\frac{300K \times320K}{320K \times300K})ln \frac{2.8}{1.2}=8.081 \times10^{3}cal\,mol^{-1}$

$=8.1\,kcal\,mol^{-1}$

Therefore, the activation energy is $=8.1\,kcal\,mol^{-1}$

8 0

3 years ago

What is the outermost (highest-energy) shell of an element that contains electrons?

DENIUS [597]

Valence shell it contains the valence electrons e.g. the outermost electro

6 0

3 years ago