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Montano1993 [528]
3 years ago
9

Number of

Chemistry
1 answer:
Sever21 [200]3 years ago
4 0

Answer:1:En química, el número másico o número de masa es la suma del número de protones y el número de neutrones del núcleo de un átomo. Se simboliza con la letra A (el uso de esta letra proviene de alemán Atomgewicht, que quiere decir peso atómico, aunque sean conceptos distintos que no deben confundirse).

2:

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Give reason brick is a solid
Elenna [48]
The brick is solid because it's not hollow or containing spaces or gaps
3 0
3 years ago
When 6.040 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 18.95 grams of CO2 and 7.759 grams of H
algol [13]

Answer: The empirical formula is CH_2 and molecular formula is C_4H_8

Explanation:

We are given:

Mass of CO_2 = 18.95 g

Mass of H_2O= 7.759 g

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 18.59 g of carbon dioxide, =\frac{12}{44}\times 18.59=5.07g of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 7.759 g of water, =\frac{2}{18}\times 7.759=0.862g of hydrogen will be contained.

Mass of C = 5.07 g

Mass of H = 0.862 g

Step 1 : convert given masses into moles.

Moles of C =\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{5.07g}{12g/mole}=0.422moles

Moles of H=\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.862g}{1g/mole}=0.862moles

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C =\frac{0.422}{0.422}=1

For H =\frac{0.862}{0.422}=2

The ratio of C : H = 1: 2

Hence the empirical formula is CH_2.

The empirical weight of CH_2 = 1(12)+2(1)= 14 g.

The molecular weight = 56.1 g/mole

Now we have to calculate the molecular formula.

n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{56.1}{14}=4

The molecular formula will be=4\times CH_2=C_4H_8

6 0
3 years ago
22. Which one of the following processes has a negative value for AH°?
ss7ja [257]

Answer:

C

Explanation:

A negative deltaH means that the reaction has to give up heat in order to happen. You have to treat deltaH as a reactant. So the question is do you need to add heat to the reactants to make the products. If you do, deltaH is plus.

Heat is required to make a solid go to a gas. deltaH is plus. A is not the answer.

A lot of heat is required for B (something like 400 Kj / mole. Like A, deltaH is plus and B is not the answer.

C: The liquid has to give up heat in order for the this reaction to take place. C is the answer.

D requires heat. It is not the answer.

4 0
3 years ago
1. Naturally occurring europium (Eu) consists of two isotopes was a mass of 151 and 153. Europium- 151 has an abundance of 48.03
sergejj [24]
The atomic mass of Europium is 152 amu

Work:
151(0.4803) = 72.52 amu
153(0.5197) = 79.5 amu
72.5 + 79.5 = 152 amu
3 0
3 years ago
Read 2 more answers
What is the purpose of galvanization?​
frutty [35]
Galvanizing protects from rust in a number of ways: It forms a barrier that prevents corrosive substances from reaching the underlying steel or iron. The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.
4 0
3 years ago
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