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3 years ago

Which profession is likely to use a radiation shield?

Chemistry

2 answers:

Sidana [21]3 years ago

5 0

Answer:

astronomer

Explanation:

just took the test :)

pantera1 [17]3 years ago

3 0

Which profession is likely to use a radiation shield?
A.)dentist
B.)astronomer
C.)mathematician
D.)geologist

The answer is B: Astronomer

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What method is used for chaff from grain

Marta_Voda [28]

Answer:

Winnowing

Explanation:

Wind blows the lighter(in terms of mass) chaff from the whole grains,which are heavier(in terms of mass)

4 0

2 years ago

What could using cobalt glass be helpful to identify?

satela [25.4K]

Answer:

Using cobalt glass could be helpful to identify elements that weakly emit blue and/or violet.

Explanation:

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2 years ago

why do you need to think about polarity of the different ingredients in your salad dressing in order for it to turn out well?

vazorg [7]

So that they combine smoothly and you aren't left with separated looking salad dressing. With polarity only, like-polarities dissolve like-polarities. So you must make sure that all your ingredients are polar or all are nonpolar.

3 0

3 years ago

Read 2 more answers

Magnesium metal burns in air to form a mixture of magnesium oxide (MgO, M = 40.31) and magnesium nitride (Mg3N2, M = 100.95). A

dedylja [7]

Answer:

26.95 %

Explanation:

Air contains the highest percentage of oxygen and nitrogen gases. Magnesium then combines with both of the gases:

$2 Mg (s) + O_2 (g)\rightarrow 2 MgO (s)$

$3 Mg (s) + N_2 (g)\rightarrow Mg_3N_2 (s)$

Firstly, find the total number of moles of magnesium metal:

$n_{Mg} = \frac{1.000 g}{24.305 g/mol} = 0.041144 mol$

Let's say that x mol react in the first reaction and y mol react in the second reaction. This means:

$x + y = 0.041144 mol$

According to stoichiometry, we form:

$n_{MgO} = x mol, n_{Mg_3N_2} = \frac{y}{3} mol$

Multiplying moles by the molar mass of each substance will yield mass. This means we form a total of:

$m_{MgO} = 40.31x g, m_{Mg_3N_2} = \frac{y}{3} 100.95 g =$

The total mass is given, so we have our second equation to solve:

$40.31x + 33.65y = 1.584$

We have two unknowns and two equations, we may then solve:

$x + y = 0.041144$

$40.31x + 33.65y = 1.584$

Express y from the first equation:

$y = 0.041144 - x$

Substitute into the second equation:

$40.31x + 33.65(0.04144 - x) = 1.584$

$40.31x + 1.39446 - 33.65x = 1.584$

$6.66x = 0.18954$

$x = 0.028459$

$y = 0.041144 - x = 0.012685$

Moles of nitride formed:

$n_{Mg_3N_2} = \frac{y}{3} = 0.0042282 mol$

Convert this to mass:

$m_{Mg_3N_2} = 0.0042282 mol\cdot 100.95 g/mol = 0.4268 g$

Find the percentage:

$\omega_{Mg_3N_2} = \frac{0.4268 g}{1.584 g}\cdot 100\% = 26.95 \%$

7 0

3 years ago

Tell how many moles of each element are in the following amounts of each compound

qwelly [4]

Take note of the subscript written for each element in the compound. To find the total number of moles, make sure to multiply the subscript with the number of moles of compound. The answer for each is written below:

a. 3*1 = 3 moles Nitrogen; 3*3 = 9 moles Hydrogen
b. 0.25*2 = 0.5 moles Hydrogen; 0.25*1 = 0.25 moles Oxygen
c. 5*2 = 10 moles Hydrogen; 5*1 =5 moles Sulfur; 5*4 = 20 moles Oxygen
d. 0.75*1 = 0.75 moles Calcium; 0.75*1*2 = 1.5 moles Nitrogen; 0.75*3*2 = 4.5 moles Oxygen

7 0

3 years ago