The answer is B. 45k. Human bodies contain approximately 60 to 70% water.
1) Calcium carbonate comprises 40.0% calcium by weight.
M(CaCO₃)=100.1 g/mol
M(Ca)=40.1 g/mol
w(Ca)=40.1/100.1=0.400 (which is 40.0%)!
2) The mass fraction mentioned is superfluous information.
3) The resulting solution is:
m(Ca)=1.2 g
m(CaCO₃)=M(CaCO₃)*m(Ca)/M(Ca)
m(CaCO₃)=100.1g/mol*1.2g/40.1g/mol=3.0 g
Answer:
Explanation:
Diethyl malonate possesses greater acidity compared to monocarbonyl substances (pKa=13) because its alpha hydrogens are linked to two carbonyl groups. Consequently, the malonic ester can be readily changed into its enolate ion by reacting it with sodium ethoxide in ethanol. When the malonic ester undergoes alkylation, a hydrogen atom in the alpha position becomes acidic, permitting another round of alkylation to yield a dialkylated malonic ester.
In this scenario, when diethyl malonate interacts with urea in the presence of sodium ethoxide base, the second alkylation step occurs within the molecule, producing a cyclic compound known as barbituric acid.
Explanation:
Filtration serves as a method of separation where solid particles that are suspended in a liquid are isolated by passing the mixture through filter paper's pores. This process ensures that the solid particles accumulate on the filter paper and the liquid flows out through the filter paper's pores.
The ordered sequence of the steps provided is:
- Measure and fold the filter paper.
- Insert the filter paper into the funnel, then position the funnel above the Erlenmeyer flask.
- Let the solid/liquid mixture pass through the filter.
- Rinse the filter paper that holds the mixture with water.
- Measure the weight of the dry filter paper along with the copper.
Answer:
This is a satellite that gathers information on rainfall and snow.
• Its orbit spans 90 percent of the Earth's surface.
• The sensors detect microwaves.
Explanation:
Right on track
