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2 years ago

Is helium a gas, liquid or solid at room temperature

1 answer:

7 0

Helium is a gas at room temperature, which means it can be used in balloons to make them float since helium is less dense than air. Hope this helps! :)

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Mercury has a density of <br> 13.55 g/mL .What would be the volume of a 122 g sample?

Salsk061 [2.6K]

Answer:

V = 9.0037

Explanation:

V = M/D

V = 122/13.55

V = 9.0037

4 0

2 years ago

Which factor has the greatest effect on the melting point of a crystalline solid

slava [35]

Inter-molecular forces. The greater the attraction between particles the more energy required to break the forces or "melt" them.

Please mark as brainliest if satisfied with answer.

7 0

2 years ago

Read 2 more answers

Iodine-131 is a radioactive isotope with a half-life of 8 days. how many grams of a 64 g sample of iodine-131 will remain at the

icang [17]

At the end of 24 days, there will only be 16 g.

7 0

2 years ago

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

2 years ago

A 10g vial must have 45ml of diluent added to it. it has a powder volume of 5ml. how many mgr will be in each ml of the final so

Semenov [28]

The solution has a concentration 20 mgr in each mL of the final solution.

To solve this problem, we need to know about concentration. The concentration formula can be defined as how much the mass per unit volume is. It can be written as

M = m/V

where M is concentration, m is mass of solute, V is the total volume of solution.

From the text we know that :

m = 10g

vsolvent = 45mL

vsolute = 5 mL

find the total volume (V)

V = vsolvent + vsolute

V = 45 + 5

V = 50mL

Then, find the concentration

M = m/V

M = 10gr / 50 mL

M = 1000 mgr / 50mL

M = 20 mgr / mL

Hence, the solution has a concentration 20 mgr in each mL of the final solution.

Find more on concentration at: brainly.com/question/17206790

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6 0

1 year ago