What is the enthalpy change for this reaction?

What is the percent composition of the u.s quarter, which has the mass of 5.670g

Vitek1552 [10]

The percent composition of each element can be calculated as follows:
% composition = (mass of element / total mass) * 100

The total mass of the quarter is given to be 5.670 grams
Mass of Cu = 5.198 grams
Mass of Ni = 0.472 grams

Substitute in the above equation to get the mass percentage of each element as follows:
% of Cu = (5.198/5.670) * 100 = 91.675%
% of Ni = (0.472/5.670) * 100 = 8.325%

6 0

3 years ago

A student has a large number of coins of different diameters, all made by the same metal. She wishes to find the density of the

Elenna [48]

Answer:

A. In a graduated cylinder, put some quantity of water and measure the initial volume. Then put a coin and measure the volume. To find the volume of the coin, simply subtract the initial volume (water only) from the ending volume (water + coin). To measure the mass, take a dry coin and place it on an electronic scale. Density = mass / volume, so divide the mass by the volume to calculate the density of the coin.

B. When measuring the volume, make sure to look at the graduated cylinder at eye level and read from the bottom of the meniscus.

6 0

2 years ago

For each of the following compounds, state whether it is ionic or covalent, and if it is ionic, write the symbols for the ions i

kupik [55]

Answer :

Covalent compound : It is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound.

The covalent compound are usually formed when two non-metals react.

Ionic compound : It is defined as the compound which is formed when electron gets transferred from one atom to another atom.

All the polyatomic ions always form an ionic compound.

Polyatomic ions : It is a charged species that composed of two or more atoms and these charged species are bonded by the covalent bond.

For the given options:

Option A: $KClO_4$

This compound is formed by the combination of potassium, $K^+$ which is a metal and $ClO_4^-$ ion which is a polyatomic ion. Thus, it will form an ionic compound.

Option B: $Mg(C_2H_3O_2)_2$

This compound is formed by the combination of magnesium, $Mg^{2+}$ which is a metal and $C_2H_3O_2^{-}$ ion which is a polyatomic ion. Thus, it will form an ionic compound.

Option C: $H_2S$

Hydrogen and sulfur, both are non-metals and they will form a covalent compound.

Option D: $Ag_2S$

This compound is formed by the combination of silver, $Ag^{+}$ which is a metal and sulfur, $S^{2-}$ which is a non-metal. Thus, it will form an ionic compound.

Option E: $N_2Cl_4$

Nitrogen and chlorine, both are non-metals and they will form a covalent compound.

Option F: $Co(NO_3)_2$

This compound is formed by the combination of cobalt, $Co^{2+}$ which is a metal and $NO_3^{-}$ ion which is a polyatomic ion. Thus, it will form an ionic compound.

6 0

2 years ago

5. Before vehicle emissions were well-regulated CO emissions were 66 g/mile. Assume this emission rate applies for an airshed. T

Aleks [24]

Answer:CALINE4 Model and Geographical Information System were used for

the present study to predict the CO concentrations and prepare thematic

maps for the study area.

CALINE4 is a latest model that predicts the concentration of carbon

monoxide impacts near the roadways. The California Department of

Transformation (CALTRANS) developed the model and its purpose is to help

planners protect public health from the adverse effects of carbon monoxide.

The model predictions along with the aid of GIS based model help to arrive at

air shed levels of carbon monoxide. CALINE4 is a simple line source

Gaussian plume dispersion model. The user defines the proposed roadway

geometry, worst-case meteorological parameters, anticipated traffic volumes

and receptor positions to predict the concentrations of pollutant.

CALINE4 is graphical with windows based user interface, designed to

ease data entry and increase the online help capabilities. The model was

developed for predicting the concentrations of relatively inert pollutants such

as carbon monoxide and it is now used for several other pollutants like NO2

and SPM. The model is based on fine tuned Gaussian diffusion equation and

it employs mixing zone concept to characterize the pollutant dispersion over

the roadways. Given the exhaust emission concentrations, meteorology and

site geometry, the model can predict the concentration of pollutants for any experimentation

Explanation:

4 0

3 years ago

Please help, and answer as much as you can.

n200080 [17]

Answer:

∴ Fractional distillation is the technique used to separate the fraction

Explanation:

A: Refinery gas

B: Gasoline fraction

C: Naphtha

D: Kerosene

E: Diesel Oil

F: Fuel oil fraction

G: Lubricating fraction

H: Bitumen

5 0

2 years ago