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r-ruslan [8.4K]
3 years ago
13

Which group was fighting communists in Nicaragua in the 1980s?

Chemistry
1 answer:
stira [4]3 years ago
7 0
The answer is A, the contras  x Good luck!! :)

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Did changing the concentration of the solid effect the change in temperature of the reaction?
wolverine [178]
I’m pretty sure it’s true
7 0
3 years ago
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Element X had a mass of 300g and a 1/2 life of 10 years. how many grams will remain after 40 years?
kiruha [24]
<h3>Answer:</h3>

18.75 grams

<h3>Explanation:</h3>
  • Half-life refers to the time taken by a radioactive material to decay by half of the original mass.
  • In this case, the half-life of element X is 10 years, which means it takes 10 years for a given mass of the element to decay by half of its original mass.
  • To calculate the amount that remained after decay we use;

Remaining mass = Original mass × (1/2)^n, where n is the number of half-lives

Number of half-lives = Time for the decay ÷ Half-life

                                 = 40 years ÷ 10 years

                                  = 4

Therefore;

Remaining mass = 300 g × (1/2)⁴

                            = 300 g × 1/16

                             = 18.75 g

Hence, a mass of 300 g of an element X decays to 18.75 g after 40 years.

3 0
3 years ago
What is the difference between an Isotope and an Allotrope?
Kaylis [27]
Allotropes are elements on the periodic table that have more than one crystalline form . There are three forms of the element carbon : Diamond, Graphite, and Fullerenes. Isotopes are atoms of the same element with the same atomic number but have a different mass number.
8 0
3 years ago
15.3 g of nano3 were dissolved in 100g of water in a calorimeter. The temperature of the water drops from 25.00°c to 21.56°c. Ca
Arturiano [62]

Answer:

0.259 kJ/mol ≅ 0.26 kJ/mol.

Explanation:

  • To solve this problem, we can use the relation:

<em>Q = m.c.ΔT,</em>

where, Q is the amount of heat absorbed by ice (Q = ??? J).

m is the mass of the ice (m = 100.0 g).

c is the specific heat of water (c of ice = 4.186 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = 21.56°C - 25.0°C = -3.44°C).

<em>∵ Q = m.c.ΔT</em>

∴ Q = (100.0 g)(4.186 J/g.°C)(-3.44°C) = -1440 J = -1.44 kJ.

<em>∵ ΔH = Q/n</em>

n = mass/molar mass = (100.0 g)/(18.0 g/mol) = 5.556 mol.

∴ ΔH = (-1.44 kJ)/(5.556 mol) = 0.259 kJ/mol ≅ 0.26 kJ/mol.

3 0
3 years ago
What is the molar mass of 81.50 g of gas
garik1379 [7]

The molar mass  of gas = 238.29 g/mol

<h3>Further explanation</h3>

Given

mass = 81.5 g

P=1.75 atm

V=4.92 L

T=307 K

Required

molar mass

Solution

The gas equation can be written  

\large{\boxed{\bold{PV=nRT}}

\tt n=\dfrac{mass}{molar~mass}

So the equation becomes :

\tt Molar~mass=\dfrac{mRT}{PV}

Input the value :

\tt M=\dfrac{81.5\times 0.082\times 307}{1.75\times 4.92}\\\\M=238.29~g/mol

5 0
2 years ago
Read 2 more answers
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