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Lemur [1.5K]
3 years ago
8

Which of the following elements has the same number of valence electrons as aluminum?

Chemistry
2 answers:
Andrei [34K]3 years ago
7 0
Boron is the correct answer
Zinaida [17]3 years ago
6 0

Answer:

boron

Explanation:

Boron and aluminum lie in same group in modern periodic table and both have three valence electrons

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2) which statement describes ionic bonding?
garik1379 [7]

Answer

odpowiedzi   d

Explanation

taka jest reguła

7 0
3 years ago
1. Naturally occurring europium (Eu) consists of two isotopes was a mass of 151 and 153. Europium- 151 has an abundance of 48.03
sergejj [24]
The atomic mass of Europium is 152 amu

Work:
151(0.4803) = 72.52 amu
153(0.5197) = 79.5 amu
72.5 + 79.5 = 152 amu
3 0
3 years ago
Read 2 more answers
This is 25 points. Pick any of the 6 questions and show how you did it. I just need to see how you do it and get the answer. You
FromTheMoon [43]
I choose question 1, so molarity is the concentration of a soulution expressed as the number of moles of solute by the litress of soulution. to get molarity you divide the moles of soulute by the litress of solution. soo 1 calculate the number of moles of solute present. 2 Calculate the number of litress solution present. 3. divide the number of moles of solute by the number of litress of solution
soo 1 mol of NaOH has a mass of 40.00 g, so moles of NaOH= 26.7. 1 mole divided 40.00 = 0.375. litress of solution = 650 g. im not sure why its a g i usally do it Ls so i guess its the way your teacher wants you to do it so do you know how to do that. so molarity = moles of solute and litress solution. sorry this probably didnt help i just wanted to add something that might help. im still working on this stuff myself hope this helps.
5 0
3 years ago
How many Joules are released to cool 250.0 grams of liquid water from 100°C to 0°C? The specific heat of water is 4.180 J/g.C.
nlexa [21]

\bold{\huge{\orange{\underline{ Solution}}}}

\bold{\underline{ Given :- }}

  • <u>We </u><u>have </u><u>250g </u><u>of </u><u>liquid </u><u>water </u><u>and </u><u>it </u><u>needs </u><u>to </u><u>be </u><u>cool </u><u>at </u><u>temperature </u><u>from </u><u>1</u><u>0</u><u>0</u><u>°</u><u> </u><u>C </u><u>to </u><u>0</u><u>°</u><u> </u><u>C</u>
  • <u>Specific </u><u>heat </u><u>of </u><u>water </u><u>is </u><u>4</u><u>.</u><u>1</u><u>8</u><u>0</u><u>J</u><u>/</u><u>g</u><u>°</u><u>C</u>

\bold{\underline{ To \: Find :- }}

  • <u>We </u><u>have </u><u>to </u><u>find </u><u>the</u><u> </u><u>total</u><u> </u><u>number </u><u>of </u><u>joules </u><u>released</u><u>. </u>

\bold{\underline{ Let's \:Begin:- }}

<u>We </u><u>know </u><u>that</u><u>, </u>

Amount of heat energy = mass * specific heat * change in temperature

<u>That </u><u>is, </u>

\sf{\red{ Q = mcΔT }}

<u>Subsitute </u><u>the </u><u>required </u><u>values </u><u>in </u><u>the </u><u>above </u><u>formula </u><u>:</u><u>-</u>

\sf{ Q = 250 × 4.180 ×(0 - 100 )}

\sf{ Q = 250 × 4.180 × - 100 }

\sf{ Q = 250 × - 418}

\sf{\pink{ Q = - 104,500 J }}

Hence, 104,500 J of heat is released to cool 250 grams of liquid water from 100° C to 0° C.

\bold{\underline{ Now :- }}

<u>We </u><u>have </u><u>to </u><u>tell </u><u>whether </u><u>the </u><u>above </u><u>process </u><u>is </u><u>endothermic </u><u>or </u><u>exothermic </u><u>:</u><u>-</u>

Here, In the above process ΔT is negative and as a result of it Q is also negative that means above process is Exothermic

  • <u>Exothermic </u><u>process </u><u>:</u><u>-</u><u> </u><u>It </u><u>is </u><u>the </u><u>process </u><u>in </u><u>which </u><u>heat </u><u>is </u><u>evolved </u><u>. </u>
  • <u>Endothermic </u><u>process </u><u>:</u><u>-</u><u> </u><u>It </u><u>is </u><u>the </u><u>process </u><u>in </u><u>which </u><u>heat </u><u>is </u><u>absorbed </u><u>.</u>
4 0
2 years ago
Write an equation and solve the problem.
VMariaS [17]
Dexter already has 4 and he gets 38 so 4+38=42. Than 42/6=7. 7 plates on each table.
4 0
3 years ago
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