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3 years ago

Gold has density of 19.3 g/cm3; how many grams of gold are in a 16.0 cm3 gold bar?

1 answer:

6 0

To determine the mass of gold, we simply multiply the density and volume. Density is a value for mass, such as kg, divided by a value for volume, such as m3. Density is a physical property of a substance that represents the mass of that substance per unit volume. We do as follows:

mass = density x volume
mass = 19.3 g/cm^3 ( 16.0 cm^3 )
mass = 308.8 g

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What does the frequency of a wave represent? A. the distance between two consecutive crests B. the number of wave cycles that pa

zepelin [54]

The frequency of a wave represents B. the number of wave cycles that pass through a specific point within a given time.

The distance between two consecutive crests and the length of a wave are the wavelength.

The distance between the highest and lowest points of a wave is twice the amplitude.

6 0

3 years ago

how many moles of sodium are needed to react with sulfuric acid to produce 3.75 moles of sodium sulfate according to the followi

anastassius [24]

Hello!

You'll need to react 7,5 moles of Sodium with sulfuric acid to produce 3.75 moles of sodium sulfate

First of all, you need to balance the reaction. The balanced reaction is shown below (ensuring that the Law of Conservation of Mass is met on both sides):

2Na + H₂SO₄ → Na₂SO₄ + H₂

Now, all that you have to do is to use molar equivalences in this reaction applying the coefficients to calculate the moles of Sodium that you'll need:

$molesNa=3,75moles Na_{2} SO_4* \frac{2 moles Na}{1 mol Na_{2} SO_4} =7,5 moles Na$

Have a nice day!

5 0

3 years ago

The instruction booklet for your pressure cooker indicates that its highest setting is 11.8 psipsi . You know that standard atmo

zavuch27 [327]

Answer: The temperature at which the food will cook is 219.14°C

Explanation:

To calculate the final temperature of the system, we use the equation given by Gay-Lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

$\frac{P_1}{T_1}=\frac{P_2}{T_2}$

where,

$P_1\text{ and }T_1$ are the initial pressure and temperature of the gas.

$P_2\text{ and }T_2$ are the final pressure and temperature of the gas.

We are given:

$P_1=14.7psi\\T_1=273K\\P_2=(14.7+11.8)psi=26.5psi\\T_2=?$

Putting values in above equation, we get:

$\frac{14.7psi}{273K}=\frac{26.5psi}{T_2}\\\\T_2=\frac{26.5\times 273}{14.7}=492.14K$

Converting the temperature from kelvins to degree Celsius, by using the conversion factor:

$T(K)=T(^oC)+273$

$492.14=T(^oC)+273\\\\T(^oC)=219.14^oC$

Hence, the temperature at which the food will cook is 219.14°C

7 0

3 years ago

Howtocalculatethevolumeofcarbondioxideproducedwhen400gofmarblewereats.t.p

lys-0071 [83]

Answer:

so 0.15 moles X 22.4 dm3/mole=3.36 dm3. Next we find the moles of hexane combusted, and then the moles of CO2. Finally, we find the volume of CO2 using the fact that at STP, 1 mole of gas = 22.4 dm3.

3 0

3 years ago

An excess of mg(s) is added to 100.ml of 0.400 m hcl. at 0c and 1 atm pressure, what volume of h 2 (g) can be obtained?

ra1l [238]

The balanced equation for the reaction between Mg and HCl is as follows
Mg + 2HCl --> MgCl₂ + H₂
stoichiometry of HCl to H₂ is 2:1

number of HCl moles reacted - 0.400 mol/L x 0.100 L = 0.04 mol of HCl
since Mg is in excess HCl is the limiting reactant
number of H₂ moles formed - 0.04/2 = 0.02 mol of H₂

we can use ideal gas law equation to find the volume of H₂
PV = nRT
where
P - pressure - 1 atm x 101 325 Pa/atm = 101 325 Pa
V - volume
n - number of moles - 0.02 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature in Kelvin - 0 °C + 273 = 273 K
substituting these values in the equation

101 325 Pa x V = 0.02 mol x 8.314 Jmol⁻¹K⁻¹ x 273 K
V = 448 x 10⁻⁶ m³
V = 448 mL
therefore answer is
c. 448 mL

5 0

3 years ago