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3 years ago

What is the mass, in grams, of a sample of 6.98 × 1024 atoms of magnesium (Mg)?

1 answer:

monitta3 years ago

5 0

N=6.98*10²⁴
Nₐ=6.022*10²³ mol⁻¹

n(Mg)=N/Nₐ

m(Mg)=n(Mg)M(Mg)=M(Mg)N/Nₐ

m(Mg)=24.3g/mol*6.98*10²⁴/(6.022*10²³mol⁻¹)=281.7 g

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A cylinder of compressed gas has a volume of 350 ml and a pressure of 931 torr. What volume in Liters would the gas occupy if al

hodyreva [135]

Answer:

$0.384\ \text{L}$

Explanation:

$P_1$ = Initial pressure = 931 torr = $931\times \dfrac{101.325}{760}=124.12\ \text{kPa}$

$P_2$ = Final pressure = 113 kPa

$V_1$ = Initial volume = 350 mL

$V_2$ = Final volume

From the Boyle's law we have

$P_1V_1=P_2V_2\\\Rightarrow V_2=\dfrac{P_1V_1}{P_2}\\\Rightarrow V_2=\dfrac{124.12\times 350}{113}\\\Rightarrow V_2=384.44\ \text{mL}=0.384\ \text{L}$

The volume the gas would occupy is $0.384\ \text{L}$ .

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2 years ago

Which of the following is a polyatomic ion? O A. HCI O B. Na O C. PO, O D. 52

timurjin [86]

I'm not the best with science but I believe the answer is B. Na.

8 0

3 years ago

Read 2 more answers

iron has a density of 7.86 g cm3 could a block of metal with a mass of 18.2 and a volume of 2.56 cm^3 be iron?

satela [25.4K]

The density of the block will be "7.11 gm/cm³". A further explanation is provided below.

Given values are:

Density of iron,

$7.86 \ g/cm^3$

Mass of block of metal,

$18.2 \ gm$

Volume of block,

$2.56 \ cm^3$

By using the formula,

→ $Density = \frac{Mass}{Volume}$

then,

→ The density of block will be:

= $\frac{Mass}{Volume}$

= $\frac{18.2}{2.56}$

= $7.11 \ gm/cm^3$

Learn more:

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2 years ago

Convert 7.50 mol of Li₂O to grams

Natali5045456 [20]

Answer:

223.5 g

Explanation:

The formula between the number of moles, mass and Mr can be used to convert moles to grams.

Number of moles = mass ÷ Mr

So, mass = number of moles × Mr

Mr of Li₂O = (6.9 × 2) + 16 = 29.8

∴ Mass = 7.5 × 29.8 = 223.5 g

4 0

2 years ago

Need answer ASAP!! The specific heat capacity of metal A is twice that of metal B. Based on

AURORKA [14]

Answer:

last choice

Explanation:

Specific heat of a metal is j/kg-c

It says nothing about melting point or heat of fusion

A = twice B = 2 * j/kg-c B = j/kg-c

if j is constant and mass is the same we can write this more like

A = 2 /C and B = 1/C

or A ~ C/2 and B~ C

now you can see that the temp change in A will be 1/2 that of B

4 0

1 year ago