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valina [46]
3 years ago
13

Chemical equations are used to model

Chemistry
1 answer:
Daniel [21]3 years ago
7 0

Answer:

C. chemical reactions

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Can a mini fridge still be used if you break the freezer
Romashka [77]
The fridge part can, just not the freezer, I think.
8 0
4 years ago
What is the molecular formula of a compound made of 25.9% N and 74.1% O?
Inessa05 [86]


D.

If we take a sample of 100g of the given compound, we should find that it contains 74.1g of oxygen and 25.9g of nitrogen. The molar masses of oxygen and nitrogen are approximately 16.0g/mol and 14.0g/mol respectively. To find the appropriate number of moles of oxygen and nitrogen found in one mole of the given compound, we divide the mass of the sample by the molar mass of each substance.

For oxygen: 74.1g/(16.0g/mol) = 4.63125 mol (round up to 5 mol)

For nitrogen: 25.9g/(14.0g/mol) = 1.85 mol (round up to 2 mol)

Therefore one mole of this compound contains 2 moles of nitrogen and 5 moles of oxygen.

8 0
3 years ago
Read 2 more answers
Blood is maintained at a pH of 7.4 by the primary buffers in the plasma and secondary buffers in the erythrocytes. The plasma co
Alinara [238K]

Answer:

74.456.6.4.7.5.3.33-6.57

Explanation:

4 0
4 years ago
What is the balanced equation for sodium reacts with water to form sodium hydroxide and hydrogen gas
Natali [406]

Answer:

2Na + 2H2O - - - > 2NaOH + H2

Explanation: This is a an exothermic reaction.

Exothermic reaction : a reaction in which heat is released during a reaction with the product

7 0
4 years ago
After 15 minutes, 30 g of a sample of polonium-218 remain unchanged. If the original sample had a mass of 960 g, what is the hal
Keith_Richards [23]
Q1. The answer is 3 minutes.

Let's first calculate the remaining amount in percent:
If 960g is 100 percent (starting amount), 30 g is how many percents:
960 g : 100% = 30 g : x
x = 30 g * 100% / 960 g = 3.125% = 0.03125

Now, using the formula to calculate the number of half-lives:
(1/2)ⁿ = x,
where
x is the remaining amount: x = 0.03125
n is the number of half-lives
1/2 stands for half-life.

(1/2)ⁿ = 0.03125
⇒ n*log(1/2) = log(0.03125) 
    n = log(0.03125)/log(1/2) = log(0.03125)/log(0.5) = -1.505/-0.301 ≈ 5

The number of half-lives is 5.
Now, <span>the number of half-lives (n) is a quotient of total time elapsed (T) and length of half-life (L):
n = T/L
We know:
n = 5
T = 15 min
L = ?

Thus
L = T/n
L = 15 min/5 = 3 minutes

Q2. Filtration should be chosen.
Filtration and distillation are used to separate mixtures - filtration for the separation of heterogeneous mixtures and </span>distillation for the separation of homogeneous mixtures. Imagine that your pile of soil is a mixture. It consists of different components (the leaves, acorns, twigs), so it is the heterogeneous mixture. Therefore, to separate the leaves, acorns, twigs you will use filtration.
5 0
4 years ago
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