1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
gladu [14]
3 years ago
11

Write the symbol for every chemical element that has atomic number greater than 55 and atomic mass less than 144.0 u

Chemistry
1 answer:
laila [671]3 years ago
3 0
You will need a periodic table to help you answer this problem. The atomic numbers are arrange from lowest to highest in the periodic table. You can locate element number 55 to be Cesium with an atomic weight of 132.905 amu. So, you start from element 56. The following elements are:

56     Barium       137.328 amu
57     Lanthanium   138.905 amu
58     Cerium       140.116 amu
59     <span>Praseodymium    140.908 amu
60     Neodymium   144.243 amu

Neodymium is already greater than 144 amu. Therefore, these elements only include Barium, Lanthanium, Cerium and Praseodymium.</span>
You might be interested in
What is the formula of the ionic compound formed by the elements lithium and oxygen?
kozerog [31]
The formula is Letter A) Li2<span>O 

i got 5 out of 5 on this test on plato.</span>
6 0
3 years ago
Read 2 more answers
Air containing 20.0 mol% water vapor at an initial pressure of 1 atm absolute is cooled in a 1- liter sealed vessel from 200°C t
chubhunter [2.5K]

Answer:

This solution is quite lengthy

Total system = nRT

n was solved to be 0.02575

nH20 = 0.2x0.02575

= 0.00515

Nair = 0.0206

PH20 = 0.19999

Pair = 1-0.19999

= 0.80001

At 15⁰c

Pair = 0.4786atm

I used antoine's equation to get pressure

The pressure = 0.50

2. Moles of water vapor = 0.0007084

Moles of condensed water = 0.0044416

Grams of condensed water = 0.07994

Please refer to attachment. All solution is in there.

6 0
3 years ago
The molecular weight of acetic acid is
kolezko [41]

Answer:

60.052 grams per mole

8 0
3 years ago
Ka/KbMIXED PRACTICE108.Calculate the [H3O+(aq)], the pH, and the % reaction for a 0.50 mol/L HCN solution. ([H3O+(aq)] = 1.8 x 1
NeTakaya

Answer:

a) [H₃O⁺] = 1.8x10⁻⁵ M

b) pH = 4.75

c) % rxn = 3.5x10⁻³ %

Explanation:

a) The dissociation reaction of HCN is:

HCN(aq) + H₂O(l) ⇄ H₃O⁺(aq) + CN⁻(aq)

0.5 M - x                       x               x

The dissociation constant from the above reactions is given by:

Ka = \frac{[H_{3}O^{+}][CN^{-}]}{[HCN]} = 6.17 \cdot 10^{-10}

6.17 \cdot 10^{-10} = \frac{x*x}{(0.5 - x)}

6.17 \cdot 10^{-10}*(0.5 - x) - x^{2} = 0

By solving the above quadratic equation we have:

x = 1.75x10⁻⁵ M = 1.8x10⁻⁵ M = [H₃O⁺] = [CN⁻]

Hence, the [H₃O⁺] is 1.8x10⁻⁵ M.

b) The pH is equal to:

pH = -log[H_{3}O^{+}] = -log(1.75 \cdot 10^{-5} M) = 4.75    

Then, the pH of the HCN solution is 4.75.

c) The % reaction is the % ionization:

\% = \frac{x}{[HCN]} \times 100

\% = \frac{1.75 \cdot 10^{-5} M}{0.5 M} \times 100

\% = 3.5 \cdot 10^{-3} \%          

Therefore, the % reaction or % ionization is 3.5x10⁻³ %.

I hope it helps you!      

6 0
2 years ago
What can you summarize about the use of acid-base indicators?
densk [106]

An acid-base indicator is used to identify the presence of an acid or base. These indicators exhibit different colors depending on the solution that they are in. They are especially useful when completing titrations to determine the molarity of an unknown substance and is denoted as option D.

<h3>What is Titration?</h3>

This is done in the laboratory and involves the slow addition of one solution of a known concentration to a known volume of another solution of unknown concentration.

Acid-base indicators are used to determine the presence of an acid or base in a solution which is based on the colors seen when performing the chemical reaction.

It is used to calculate the the molarity of an unknown substance through the knowledge of the other parameters which is therefore the reason why option D was chosen as the most appropriate choice.

Read more Acid-base indicators  here brainly.com/question/2815636

#SPJ1

6 0
1 year ago
Other questions:
  • ASAP Which of these mixtures would best be separated through distillation?
    6·1 answer
  • Which of the following rocks would you most likely find in a cave? conglomerate foliated metamorphic rock chemical sedimentary r
    9·2 answers
  • How much heat is absorbed by 0.060 kg of copper when it is heated from 20.0°C to 80.0°C if the specific heat of copper is 385J/k
    14·1 answer
  • Calculate the ph of a blood plasma sample with a total co2 concentration of 25.6 mm and bicarbonate concentration of 24.3 mm. th
    10·1 answer
  • For the following reaction, 30.1 grams of carbon disulfide are allowed to react with 95.9 grams of chlorine gas. carbon disulfid
    9·1 answer
  • How much heat is required to warm 1.30 l of water from 24.0 ∘c to 100.0∘c? (assume a density of 1.0g/ml for the water.)?
    10·1 answer
  • For the following reactions, the ΔH° rxn is not equal to ΔH° f for the product except for ________.
    10·1 answer
  • The proton has a mass of?
    6·1 answer
  • According to the equation 2Na + 2H2O mc012-1.jpg 2NaOH+H2, what mass of Na is required to yield 22.4 L of H2 at STP? (The atomic
    9·2 answers
  • What can you determine about an element if you only know its group number on the periodic table?
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!