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nydimaria [60]
3 years ago
14

An atom of helium-4 differs from an atom of lithium-7 in that the atom of helium-4 has?

Chemistry
1 answer:
lianna [129]3 years ago
4 0
2.valence electrons while lithium has 5
You might be interested in
What is the percentage of oxygen in Li(NO2)3
BartSMP [9]

Answer:

66.2 % of O

Explanation:

Our compound is the lithium nitrite.

LiNO₂

This salt is ionic and can be dissociated: LiNO₂ →  Li⁺ + NO₂⁻

We determine the molar mass:

molar mass of Li + 3 . molar mass of N + 6 . molar mass of O

6.94 g/mol + 3. 14 g/mol + 6 . 16 g/mol = 144.94 g/mol

The mass of oxygen contained in 1 mol of lithium nitrite is:

6 . 16 g/mol = 96 g

So the percentage of oxygen present is:

(96 g / 144.94 g) . 100 = 66.2 %

3 0
3 years ago
What mass of hcl gas must be added to 1.00 l of a buffer solution that contains [aceticacid]=2.0m and [acetate]=1.0m in order to
Paraphin [41]
PH of acidic buffer = pKa + log [CH₃COONa - HCl] / [CH₃COOH + HCl]
pKa of CH₃COOH = 4.74
Concentration of acetic acid in buffer = 2.0 M
Concentration of sodium acetate = 1.0 M
Concentration of HCl must add = x
pH = 4.74 + log (1-x) / (2+x) = 4.11
x = concentration of HCl must be added = 0.43 M
number of moles of HCl = M * V = 0.43 * 1 = 0.43 mol
mass of HCl must be added = 0.43 * 36.5 = 15.7 g
 
3 0
3 years ago
What is the mass of a 1.00 l sample of a liquid that has a density of 0.967 g/ml ? express your answer using three significant f
BARSIC [14]

Mass = 1000 mL x 0.967 g/1 mL = 967 g

5 0
3 years ago
Fill in the blank. The amount which an object accelerates
KATRIN_1 [288]
I think the answer is force
6 0
3 years ago
The temperature
solniwko [45]

\quad \huge \quad \quad \boxed{ \tt \:Answer }

\texttt {The reaction releases energy}\texttt{( - or Exothermic)}

____________________________________

\large \tt Explanation  \: :

Temperature of thermometer increases during the reaction, that means it receives heat. henceforth we can conclude that energy is released during the reaction that cleary mean that it's an Exothermic Reaction.

Answered by : ❝ AǫᴜᴀWɪᴢ ❞

7 0
2 years ago
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