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alina1380 [7]
3 years ago
7

Alright who can help me?and if you dont know then dont answer ok​

Chemistry
1 answer:
Annette [7]3 years ago
8 0

Answer:

Explanation:

number 2 is climate

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In sience is copper a element or not a element
sukhopar [10]

Answer:

a element

Explanation:

In science copper is a element. It is one of the transition metals found on the periodic table of elements.

Elements are distinct substances that cannot be split-up into simpler substances. Such substances consist of one kind of atom.

There are over a hundred elements that are known till date.

Each elements combines to form a compound

7 0
2 years ago
Exactly how much time must elapse before 16 grams of potassium-42decays, leaving 2 grams of the original isotope?(1) 8 × 12.4 ho
AleksandrR [38]
The answer is <span>(3) 3 × 12.4 hours
</span>
To calculate this, we will use two equations:
(1/2) ^{n} =x
t_{1/2} = \frac{t}{n}
where:
<span>n - number of half-lives
</span>x - remained amount of the sample, in decimals
<span>t_{1/2} - half-life length
</span>t - total time elapsed.

First, we have to calculate x and n. x is <span>remained amount of the sample, so if at the beginning were 16 grams of potassium-42, and now it remained 2 grams, then x is:
2 grams : x % = 16 grams : 100 %
x = 2 grams </span>× 100 percent ÷ 16 grams
x = 12.5% = 0.125

Thus:
<span>(1/2) ^{n} =x
</span>(0.5) ^{n} =0.125
n*log(0.5)=log(0.125)
n= \frac{log(0.5)}{log(0.125)}
n=3

It is known that the half-life of potassium-42 is 12.36 ≈ 12.4 hours.
Thus:
<span>t_{1/2} = 12.4
</span><span>t_{1/2} *n = t
</span>t= 12.4*3

Therefore, it must elapse 3 × 12.4 hours <span>before 16 grams of potassium-42 decays, leaving 2 grams of the original isotope</span>
7 0
3 years ago
Read 2 more answers
What is the volume of 1.56 kg of a compound whose molar mass is 81.86 g/mole and whose density is 41.2 g/ml?
hjlf

Answer:

v = 37.9 ml

Explanation:

Given data:

Mass of compound = 1.56 kg

Density = 41.2 g/ml

Volume of compound = ?

Solution:

First of all we will convert the mass into g.

1.56 ×1000 = 1560 g

Formula:

D=m/v

D= density

m=mass

V=volume

v = m/d

v =  1560 g / 41.2 g/ml

v = 37.9 ml

7 0
3 years ago
How many grams of Mg are needed to produce 224 g of MgO in the complete reaction of Mg
zmey [24]

Answer:

134.4 g of Mg

Explanation:

reaction:

2Mg + O2 ➡️ 2MgO

1) find the mol of MgO

mol = mass / molar mass

mass = 224 g

molar mass = 24+16 = 40

mol = 224 / 40

= 5.6 moles

2 mol = 5.6 moles

2) find the mass of Mg

mass = mol × molar mass

mol = 5.6

molar mass = 24

mass = 5.6 × 24

= 134.4 g

7 0
3 years ago
Each liter of air has a mass of 1.80 grams. How many liters of air are contained in
natita [175]

Question:

Each liter of air has a mass of 1.80 grams. How many liters of air are contained in 2.5 x103) kg of air?

Answer:

11.48106 L

5 0
3 years ago
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