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3 years ago

Which of the following is not a physical change?

1 answer:

6 0

When you burn paper you are chemically altering it so that is the correct answer. When you do all the other choices all of the components stay the same. Just because it changes shapes doesn't mean it'll change chemically toom

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Of the three types of oxygen flowmeters, which one can only be used upright?

lorasvet [3.4K]

Given the choices;
a) Bourdon gauge flowmeter
b) Hudson gauge flow meter
c) Constant flow selector
d) pressure compensated flowmeter.
The one that can only be used upright is the pressure-compensated flowmeter. Compensated flowmeters work with a variable orifice and fixed pressure. They read back pressure, and take into account resistance changes down stream from the needle valve. If pressure exceeds 50psig downstream, flow ceases.

7 0

3 years ago

Dihydrogen dioxide decomposes into water and oxygen gas. Calculate the amounts requested if 1.34 moles of dihydrogen dioxide rea

a_sh-v [17]

Answers:

a. Moles of oxygen formed: 0.670 mol

b. Moles of water formed: 1.34 mol

c. Mass of water formed: 24.1 g

d. Mass of oxygen formed: 21.4 g

Explanation:

Dihdyrogen dioxide is the chemical name for a compound made of two hydrogen atoms and two oxide atoms, i.e. H₂O₂, which is also known as hydrogen peroxide or oxygenated water.

The decomposition reaction of dihydrogen dioxide into water and oxygen gas is represented by the balanced chemical equation:

$2H_2O_2(l)\rightarrow 2H_2O(l)+O_2(g)$

The mole ratios derived from that balanced chemical equation are:

2 mol H₂O₂ : 2 mol H₂O : 1 mol O₂

a. Moles of oxygen formed

Set the proportion using the theoretical mole ratio of H₂O₂ to O₂ and the amount of moles of dyhydrogen dioxide that react:

$2\text{ mol }H_2O_2/1\text{ mol }O_2=1.34\text{ mol }H_2O_2/x$

When you solve for x, you get:

x = 1.34 mol H₂O₂ × 1 mol O₂ / 2 mol H₂O₂ = 0.670 mol O₂

b. Moles of water formed

Set the proportion using the theoretical mole ratio of H₂O₂ to H₂O and the amount of moles of dyhydrogen dioxide that react:

$2\text{ mol }H_2O_2/2\text{ mol }H_2O=1.34\text{ mol }H_2O_2/x$

When you solve for x, you get:

x = 1.34 mol H₂O₂ × 2 mol H₂O / 2 mol H₂O₂ = 1.34 mol H₂O

c. Mass of water formed

Using the number of moles of water calculated in the part b., you calculate the mass of water formed, in grams, using the molar mass of water:

Molar mass of water = 18.015 g/mol

Number of moles = mass in grams / molar mass

⇒ mass in grams = number of moles × molar mass

⇒ mass in grams = 1.34 mol × 18.015 g/mol = 24.1 g

d. Mass of oxygen formed

Using the number of moles of oxygen determined in the part a., you calculate the mass in grams using the molar mass of O₂.

Molar mass of O₂ = 32.00 g/mol

mass = molar mass × number of moles

mass = 32.00 g/mol × 0.670 mol = 21.4 g.

5 0

3 years ago

At the start of the _________, about 10,000 years ago, humans began planting crops and domesticating animals.

Alex777 [14]

I think the Neolithic Revolution is the correct answer

5 0

3 years ago

HI I AM KEANU REEVES

m_a_m_a [10]

Answer:

hey

Explanation:

7 0

2 years ago

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What would be the immediate product of neutron absorption by Ag 107

Novosadov [1.4K]

The immediate product of neutron absorption by Ag-107 is silver atom with a mass of 108, Ag-108.

<h3>What is radioactivity?</h3>

Radioactivity is the spontaneous emission of radiation as wall as particles and energy l by the nucleus of elements due to their disintegration.

The radioactive particles that are usually emitted include:

alpha particles
beta particles and
neutrons

The neutron has a mass of 1.

When silver isotope having a mass of 107 absorbs a neutron, the silver isotope produces will have a mass of 108, Ag-108.

Learn more about radioactivity at: brainly.com/question/25750315

4 0

1 year ago