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3 years ago

The instrument that is commonly used to measure the intensity of radioactivity is called a _____.

Chemistry

2 answers:

Nesterboy [21]3 years ago

7 0

I think the answer is a (geiger counter)

pochemuha3 years ago

3 0

The instrument is a Geiger counter and is used to measure radioactive level around people's bodies.

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How much carbon dioxide will be formed if 12.5 grams of oxygen reacts with 7.2 grams of propane (C3H8 )? Balanced equation: C3H8

solong [7]

Answer:

10.3125 grams of carbon dioxide will be formed.

Explanation:

The balanced reaction is:

C₃H₈ + 5 O₂→ 3 CO₂ + 4 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles participate in the reaction:

C₃H₈: 1 mole
O₂: 5 moles
CO₂: 3 moles
H₂O: 4 moles

Being the molar mass of the compounds:

C₃H₈: 44 g/mole
O₂: 32 g/mole
CO₂: 44 g/mole
H₂O: 18 g/mole

then by stoichiometry of the reaction, the following amounts of mass participate in the reaction:

C₃H₈: 1 mole* 44 g/mole = 44 g
O₂: 5 moles* 32 g/mole= 160 g
CO₂: 3 moles* 44 g/mole= 132 g
H₂O: 4 moles* 18 g/mole= 72 g

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, it is possible to use a simple rule of three as follows: If by reaction stoichiometry 44 grams of propane react with 160 grams of oxygen, 7.2 grams of propane react with how much mass of oxygen?

$mass of oxygen=\frac{7.2 grams of propane*160 grams of oxygen}{44 grams of propane}$

mass of oxygen= 26.18 grams

But 26.18 moles of O₂ are not available, 12.5 grams are available. Since you have less mass than you need to react with 7.2 grams of propane, oxygen O₂ will be the limiting reagent.

Then you can apply the following rule of three: if by stoichiometry of the reaction 160 grams of oxygen form 132 grams of carbon dioxide, 12.5 grams of oxygen will form how much mass of carbon dioxide?

$mass of carbon dioxide=\frac{12.5 grams of oxygen*132 grams of carbon dioxide}{160 grams of oxygen}$

mass of carbon dioxide= 10.3125 grams

10.3125 grams of carbon dioxide will be formed.

7 0

3 years ago

Joe the scientist wants to figure out the angle for throwing a football that

Solnce55 [7]

Answer:

Explanation:

7 0

3 years ago

Read 2 more answers

What is the concentration of an unknown Mg(OH)2 solution if it took an average of 15.4mL of

vova2212 [387]

Answer:

0.077M

Explanation:

Step 1:

The balanced equation for the reaction. This is given below:

2HCl + Mg(OH)2 —> MgCl2 + 2H2O

From the balanced equation above,

The mole ratio of the acid (nA) = 2

The mole ratio of the base (nB) = 1

Step 2:

Data obtained from the question.

Concentration of base Cb =...?

Volume of base (Vb) = 10mL

Concentration of acid (Ca) = 0.1M

Volume of acid (Va) = 15.4mL

Step 3:

Determination of the concentration of the base, Mg(OH)2.

The concentration of the base can be obtained as follow:

CaVa/CbVb = nA/nB

0.1 x 15.4 /Cb x 10 = 2/1

Cross multiply to express in linear form

Cb x 10 x 2 = 0.1 x 15.4

Divide both side by 10 x 2

Cb = (0.1 x 15.4) /(10 x 2)

Cb = 0.077M

Therefore, the concentration of the base, Mg(OH)2 is 0.077M

7 0

3 years ago

Manganese dioxide (MnO2(s), Hf = –520.0 kJ) reacts with aluminum to form aluminum oxide (AI2O3(s), Hf = –1699.8 kJ/mol) and mang

Temka [501]

Answer : The enthalpy of the reaction = -1839.6 KJ

Solution : Given,

$\Delta (H_{f})_{MnO_{2}}$ = -520.0 KJ/mole

$\Delta (H_{f})_{Al_{2}O_{3}}$ = -1699.8 KJ/mole

The balanced chemical reaction is,

$3MnO_{2}(s)+4Al(s)\rightarrow 2Al_{2}O_{3}(s)+3Mn(s)$

Formula used :

$\Delta (H_{f})_{reaction}=\sum n(\Delta H_{f})_{product}-\sum n(\Delta H_{f})_{reactant}$

$\Delta (H_{f})_{reaction}=(2\times \Delta H_{Al_{2}O_{3}(s)}+3\times \Delta H_{Mn(s)} )-(3\times \Delta H_{MnO_{2}(s) }+4\times\Delta H_{Al}(s))$

We know that the standard enthalpy of formation of the element is equal to Zero.

Therefore, the enthalpy of formation of (Mn) and (Al) is equal to zero.

Now, put all the values in above formula, we get

$\Delta (H_{f})_{reaction}=[2moles\times (-1699.8 KJ/mole)}+3moles\times (0\text{ KJ/mole}})]-[(3moles\times(-520.0KJ/mole }+4moles\times(0\text{ KJ/mole})]$

= (-3399.6) + (1560)

= -1839.6 KJ

5 0

3 years ago

Which of the following is the correct equation for the reaction below?

fenix001 [56]

Answer:

Option C.

2 Mg (s) + O₂(g) → 2MgO (s)

Explanation:

Two moles of magnesium solid react with one mol of oxygen gas to

form two moles of magnesium-oxide solid

2 Mg (s) + O₂(g) → 2MgO (s)

That's the reaction for the magnessium oxide's formation.

Be careful cause we do not say molecules, they are moles.

The stoichiometry indicates the number of moles that react and the moles which are produced.

It is a redox reaction, because the magnessium is oxidized and the oxygen is reduced. Both elements, changed the oxidation states.

4 0

3 years ago

Read 2 more answers